Preclinical Efficacy of a Lipooligosaccharide Peptide Mimic Candidate Gonococcal Vaccine

ABSTRACT The global spread of multidrug-resistant strains of Neisseria gonorrhoeae constitutes a public health emergency. With limited antibiotic treatment options, there is an urgent need for development of a safe and effective vaccine against gonorrhea. Previously, we constructed a prototype vaccine candidate comprising a peptide mimic (mimitope) of a glycan epitope on gonococcal lipooligosaccharide (LOS), recognized by monoclonal antibody 2C7. The 2C7 epitope is (i) broadly expressed as a gonococcal antigenic target in human infection, (ii) a critical requirement for gonococcal colonization in the experimental setting, and (iii) a virulence determinant that is maintained and expressed by gonococci. Here, we have synthesized to >95% purity through a relatively facile and economical process a tetrapeptide derivative of the mimitope that was cyclized through a nonreducible thioether bond, thereby rendering the compound homogeneous and stable. This vaccine candidate, called TMCP2, when administered at 0, 3, and 6 weeks to BALB/c mice at either 50, 100 or 200 μg/dose in combination with glucopyranosyl lipid A-stable oil-in-water nanoemulsion (GLA-SE; a Toll-like receptor 4 and TH1-promoting adjuvant), elicited bactericidal IgG and reduced colonization levels of gonococci in experimentally infected mice while accelerating clearance by each of two different gonococcal strains. Similarly, a 3-dose biweekly schedule (50 μg TMCP2/dose) was also effective in mice. We have developed a gonococcal vaccine candidate that can be scaled up and produced economically to a high degree of purity. The candidate elicits bactericidal antibodies and is efficacious in a preclinical experimental infection model. IMPORTANCE Neisseria gonorrhoeae has become resistant to most antibiotics. The incidence of gonorrhea is also sharply increasing. A safe and effective antigonococcal vaccine is urgently needed. Lipooligosaccharide (LOS), the most abundant outer membrane molecule, is indispensable for gonococcal pathogenesis. A glycan epitope on LOS that is recognized by monoclonal antibody (MAb) 2C7 (called the 2C7 epitope) is expressed almost universally by gonococci in vivo. Previously, we identified a peptide mimic (mimitope) of the 2C7 epitope, which when configured as an octamer and used as an immunogen, attenuated colonization of mice by gonococci. Here, a homogenous, stable tetrameric derivative of the mimitope, when combined with a TH1-promoting adjuvant and used as an immunogen, also effectively attenuates gonococcal colonization of mice. This candidate peptide vaccine can be produced economically, an important consideration for gonorrhea, which affects socioeconomically underprivileged populations disproportionately, and represents an important advance in the development of a gonorrhea vaccine.

Download Full-text

Synthetic DNA Delivery of an Optimized and Engineered Monoclonal Antibody Provides Rapid and Prolonged Protection against Experimental Gonococcal Infection

mBio ◽

10.1128/mbio.00242-21 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Elizabeth M. Parzych ◽

Sunita Gulati ◽

Bo Zheng ◽

Mamadou A. Bah ◽

Sarah T. C. Elliott ◽

...

Keyword(s):

Monoclonal Antibody ◽

Neisseria Gonorrhoeae ◽

Bactericidal Activity ◽

Complement Activation ◽

Natural Infection ◽

Effective Vaccine ◽

Content Type ◽

Synthetic Dna ◽

Human Igg1

ABSTRACT Monoclonal antibody (MAb) 2C7 recognizes a lipooligosaccharide epitope expressed by most clinical Neisseria gonorrhoeae isolates and mediates complement-dependent bactericidal activity. We recently showed that a recombinant human IgG1 chimeric variant of MAb 2C7 containing an E430G Fc modification (2C7_E430G), which enhances complement activation, outperformed the parental MAb 2C7 (2C7_WT) in vivo. Because natural infection with N. gonorrhoeae often does not elicit protective immunity and reinfections are common, approaches that prolong bacterial control in vivo are of great interest. Advances in DNA-based approaches have demonstrated the combined benefit of genetic engineering, formulation optimizations, and facilitated delivery via CELLECTRA-EP technology, which can induce robust in vivo expression of protective DNA-encoded monoclonal antibodies (DMAbs) with durable serum activity relative to traditional recombinant MAb therapies. Here, we created optimized 2C7-derived DMAbs encoding the parental Fc (2C7_WT) or complement-enhancing Fc variants (2C7_E430G and 2C7_E345K). 2C7 DMAbs were rapidly generated and detected throughout the 4-month study. While all complement-engaging 2C7 variants facilitated rapid clearance following primary N. gonorrhoeae challenge (day 8 after DMAb administration), the complement-enhancing 2C7_E430G variant demonstrated significantly higher potency against mice rechallenged 65 days after DMAb administration. Passive intravenous transfer of in vivo-produced, purified 2C7 DMAbs confirmed the increased potency of the complement-enhancing variants. This study highlights the ability of the DMAb platform to launch the in vivo production of antibodies engineered to promote and optimize downstream innate effector mechanisms such as complement-mediated killing, leading to hastened bacterial elimination. IMPORTANCE Neisseria gonorrhoeae has become resistant to most antibiotics in clinical use. Currently, there is no safe and effective vaccine against gonorrhea. Measures to prevent the spread of gonorrhea are a global health priority. A monoclonal antibody (MAb) called 2C7, directed against a lipooligosaccharide glycan epitope expressed by most clinical isolates, displays complement-dependent bactericidal activity and hastens clearance of gonococcal vaginal colonization in mice. Fc mutations in a human IgG1 chimeric version of MAb 2C7 further enhance complement activation, and the resulting MAb displays greater activity than wild-type MAb 2C7 in vivo. Here, we utilized a DNA-encoded MAb (DMAb) construct designed to launch production and assembly of “complement-enhanced” chimeric MAb 2C7 in vivo. The ensuing rapid and sustained MAb 2C7 expression attenuated gonococcal colonization in mice at 8 days as well as 65 days postadministration. The DMAb system may provide an effective, economical platform to deliver MAbs for durable protection against gonorrhea.

Download Full-text

The Lst Sialyltransferase of Neisseria gonorrhoeae Can Transfer Keto-Deoxyoctanoate as the Terminal Sugar of Lipooligosaccharide: a Glyco-Achilles Heel That Provides a New Strategy for Vaccines to Prevent Gonorrhea

mBio ◽

10.1128/mbio.03666-20 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Freda E.-C. Jen ◽

Margaret R. Ketterer ◽

Evgeny A. Semchenko ◽

Christopher J. Day ◽

Kate L. Seib ◽

...

Keyword(s):

Monoclonal Antibody ◽

Neisseria Gonorrhoeae ◽

Phase Variation ◽

Multidrug Resistant ◽

Content Type ◽

Acetylneuraminic Acid ◽

New Strategy ◽

Opsonophagocytic Killing ◽

Further Development

ABSTRACT The lipooligosaccharide (LOS) of Neisseria gonorrhoeae plays key roles in pathogenesis and is composed of multiple possible glycoforms. These glycoforms are generated by the process of phase variation and by differences in the glycosyltransferase gene content of particular strains. LOS glycoforms of N. gonorrhoeae can be terminated with an N-acetylneuraminic acid (Neu5Ac), which imparts resistance to the bactericidal activity of serum. However, N. gonorrhoeae cannot synthesize the CMP-Neu5Ac required for LOS biosynthesis and must acquire it from the host. In contrast, Neisseria meningitidis can synthesize endogenous CMP-Neu5Ac, the donor molecule for Neu5Ac, which is a component of some meningococcal capsule structures. Both species have an almost identical LOS sialyltransferase, Lst, that transfers Neu5Ac from CMP-Neu5Ac to the terminus of LOS. Lst is homologous to the LsgB sialyltransferase of nontypeable Haemophilus influenzae (NTHi). Studies in NTHi have demonstrated that LsgB can transfer keto-deoxyoctanoate (KDO) from CMP-KDO to the terminus of LOS in place of Neu5Ac. Here, we show that Lst can also transfer KDO to LOS in place of Neu5Ac in both N. gonorrhoeae and N. meningitidis. Consistent with access to the pool of CMP-KDO in the cytoplasm, we present data indicating that Lst is localized in the cytoplasm. Lst has previously been reported to be localized on the outer membrane. We also demonstrate that KDO is expressed as a terminal LOS structure in vivo in samples from infected women and further show that the anti-KDO monoclonal antibody 6E4 can mediate opsonophagocytic killing of N. gonorrhoeae. Taken together, these studies indicate that KDO expressed on gonococcal LOS represents a new antigen for the development of vaccines against gonorrhea. IMPORTANCE The emergence of multidrug-resistant N. gonorrhoeae strains that are resistant to available antimicrobials is a current health emergency, and no vaccine is available to prevent gonococcal infection. Lipooligosaccharide (LOS) is one of the major virulence factors of N. gonorrhoeae. The sialic acid N-acetylneuraminic acid (Neu5Ac) is present as the terminal glycan on LOS in N. gonorrhoeae. In this study, we made an unexpected discovery that KDO can be incorporated as the terminal glycan on LOS of N. gonorrhoeae by the alpha-2,3-sialyltransferase Lst. We showed that N. gonorrhoeae express KDO on LOS in vivo and that the KDO-specific monoclonal antibody 6E4 can direct opsonophagocytic killing of N. gonorrhoeae. These data support further development of KDO-LOS structures as vaccine antigens for the prevention of infection by N. gonorrhoeae.

Download Full-text

Bypassing Phase Variation of Lipooligosaccharide (LOS): Using Heptose 1 Glycan Mutants To Establish Widespread Efficacy of Gonococcal Anti-LOS Monoclonal Antibody 2C7

Infection and Immunity ◽

10.1128/iai.00862-19 ◽

2019 ◽

Vol 88 (2) ◽

Author(s):

Srinjoy Chakraborti ◽

Sunita Gulati ◽

Bo Zheng ◽

Frank J. Beurskens ◽

Janine Schuurman ◽

...

Keyword(s):

Monoclonal Antibody ◽

Polymorphonuclear Leukocytes ◽

Phase Variation ◽

Human Infection ◽

Phase Variable ◽

Content Type ◽

Human Igg1 ◽

And Function

ABSTRACT The sialylatable lacto-N-neotetraose (LNnT; Gal-GlcNAc-Gal-Glc) moiety from heptose I (HepI) of the lipooligosaccharide (LOS) of Neisseria gonorrhoeae undergoes positive selection during human infection. Lactose (Gal-Glc) from HepII, although phase variable, is commonly expressed in humans; loss of HepII lactose compromises gonococcal fitness in mice. Anti-LOS monoclonal antibody (MAb) 2C7, a promising antigonococcal immunotherapeutic that elicits complement-dependent bactericidal activity and attenuates gonococcal colonization in mice, recognizes an epitope comprised of lactoses expressed simultaneously from HepI and HepII. Glycan extensions beyond lactose on HepI modulate binding and function of MAb 2C7 in vitro. Here, four gonococcal LOS mutants, each with lactose from HepII but fixed (unable to phase-vary) LOS HepI glycans extended beyond the lactose substitution of HepI (lactose alone, Gal-lactose, LNnT, or GalNAc-LNnT), were used to define how HepI glycan extensions affect (i) mouse vaginal colonization and (ii) efficacy in vitro and in vivo of a human IgG1 chimeric derivative of MAb 2C7 (2C7-Ximab) with a complement-enhancing E-to-G Fc mutation at position 430 (2C7-Ximab-E430G). About 10-fold lower 2C7-Ximab-E430G concentrations achieved similar complement-dependent killing of three gonococcal mutants with glycan extensions beyond lactose-substituted HepI (lactose alone, LNnT, or GalNAc-LNnT) as 2C7-Ximab (unmodified Fc). The fourth mutant (Gal-lactose) resisted direct complement-dependent killing but was killed approximately 70% by 2C7-Ximab-E430G in the presence of polymorphonuclear leukocytes and complement. Only mutants with (sialylatable) LNnT from HepI colonized mice for >3 days, reiterating the importance of LNnT sialylation for infection. 2C7-Ximab-E430G significantly attenuated colonization caused by the virulent mutants.

Download Full-text

A Cronobacter turicensis O1 Antigen-Specific Monoclonal Antibody Inhibits Bacterial Motility and Entry into Epithelial Cells

Infection and Immunity ◽

10.1128/iai.02211-14 ◽

2014 ◽

Vol 83 (3) ◽

pp. 876-887 ◽

Cited By ~ 6

Author(s):

Kristina Schauer ◽

Angelika Lehner ◽

Richard Dietrich ◽

Ina Kleinsteuber ◽

Rocío Canals ◽

...

Keyword(s):

Monoclonal Antibody ◽

Epithelial Cells ◽

Foodborne Pathogen ◽

Antimicrobial Effect ◽

Infection Model ◽

Cell Agglutination ◽

Content Type ◽

O Antigen ◽

Lethal Infection ◽

Insight Into

Cronobacter turicensisis an opportunistic foodborne pathogen that can cause a rare but sometimes lethal infection in neonates. Little is known about the virulence mechanisms and intracellular lifestyle of this pathogen. In this study, we developed an IgG monoclonal antibody (MAb; MAb 2G4) that specifically recognizes the O1 antigen ofC. turicensiscells. The antilipopolysaccharide antibody bound predominantly monovalently to the O antigen and reduced bacterial growth without causing cell agglutination. Furthermore, binding of the antibody to the O1 antigen ofC. turicensiscells caused a significant reduction of the membrane potential which is required to energize flagellar rotation, accompanied by a decreased flagellum-based motility. These results indicate that binding of IgG to the O antigen ofC. turicensiscauses a direct antimicrobial effect. In addition, this feature of the antibody enabled new insight into the pathogenicity ofC. turicensis. In a tissue culture infection model, pretreatment ofC. turicensiswith MAb 2G4 showed no difference in adhesion to human epithelial cells, whereas invasion of bacteria into Caco-2 cells was significantly inhibited.

Download Full-text

In VivoEfficacy of Anuran Trypsin Inhibitory Peptides against Staphylococcal Skin Infection and the Impact of Peptide Cyclization

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.04324-14 ◽

2015 ◽

Vol 59 (4) ◽

pp. 2113-2121 ◽

Cited By ~ 9

Author(s):

U. Malik ◽

O. N. Silva ◽

I. C. M. Fensterseifer ◽

L. Y. Chan ◽

R. J. Clark ◽

...

Keyword(s):

Antimicrobial Agents ◽

Cyclic Peptide ◽

Sequence Similarity ◽

Infection Model ◽

Content Type ◽

Wide Range ◽

Inhibitory Activities ◽

The Impact

ABSTRACTStaphylococcus aureusis a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weakin vitroinhibitory activities againstS. aureus, but several had strong antibacterial activities againstS. aureusin anin vivomurine wound infection model. pYR, an immunomodulatory peptide fromRana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg−1. Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen.

Download Full-text

Efficacy of Humanized Cefiderocol Exposures over 72 Hours against a Diverse Group of Gram-Negative Isolates in the Neutropenic Murine Thigh Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01040-18 ◽

2018 ◽

Vol 63 (2) ◽

pp. e01040-18 ◽

Cited By ~ 3

Author(s):

Sean M. Stainton ◽

Marguerite L. Monogue ◽

Masakatsu Tsuji ◽

Yoshinori Yamano ◽

Roger Echols ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Acinetobacter Baumannii ◽

Infection Model ◽

Diverse Group ◽

Gram Negative ◽

Content Type ◽

Adaptive Resistance

ABSTRACT Herein, we evaluated sustainability of humanized exposures of cefiderocol in vivo over 72 h against pathogens with cefiderocol MICs of 0.5 to 16 μg/ml in the neutropenic murine thigh model. In Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae displaying MICs of 0.5 to 8 μg/ml (n = 11), sustained kill was observed at 72 h among 9 isolates. Postexposure MICs revealed a single 2-dilution increase in one animal compared with controls (1/54 samples, 1.8%) at 72 h. Adaptive resistance during therapy was not observed.

Download Full-text

Reversal of Azole Resistance inCandida albicansby Sulfa Antibacterial Drugs

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00701-17 ◽

2017 ◽

Vol 62 (3) ◽

Cited By ~ 15

Author(s):

Hassan E. Eldesouky ◽

Abdelrahman Mayhoub ◽

Tony R. Hazbun ◽

Mohamed N. Seleem

Keyword(s):

Treatment Options ◽

Antifungal Drugs ◽

Infection Model ◽

Azole Resistance ◽

Global Public Health ◽

Sulfa Drugs ◽

Antibacterial Drugs ◽

Content Type

ABSTRACTInvasive candidiasis presents an emerging global public health challenge due to the emergence of resistance to the frontline treatment options, such as fluconazole. Hence, the identification of other compounds capable of pairing with fluconazole and averting azole resistance would potentially prolong the clinical utility of this important group. In an effort to repurpose drugs in the field of antifungal drug discovery, we explored sulfa antibacterial drugs for the purpose of reversing azole resistance inCandida. In this study, we assembled and investigated a library of 21 sulfa antibacterial drugs for their ability to restore fluconazole sensitivity inCandida albicans. Surprisingly, the majority of assayed sulfa drugs (15 of 21) were found to exhibit synergistic relationships with fluconazole by checkerboard assay with fractional inhibitory concentration index (ΣFIC) values ranging from <0.0312 to 0.25. Remarkably, five sulfa drugs were able to reverse azole resistance in a clinically achievable range. The structure-activity relationships (SARs) of the amino benzene sulfonamide scaffold as antifungal agents were studied. We also identified the possible mechanism of the synergistic interaction of sulfa antibacterial drugs with azole antifungal drugs. Furthermore, the ability of sulfa antibacterial drugs to inhibitCandidabiofilm by 40%in vitrowas confirmed. In addition, the effects of sulfa-fluconazole combinations onCandidagrowth kinetics and efflux machinery were explored. Finally, using aCaenorhabditis elegansinfection model, we demonstrated that the sulfa-fluconazole combination does possess potent antifungal activityin vivo, reducingCandidain infected worms by ∼50% compared to the control.

Download Full-text

Role of BrnQ1 and BrnQ2 in Branched-Chain Amino Acid Transport and Virulence in Staphylococcus aureus

Infection and Immunity ◽

10.1128/iai.02542-14 ◽

2014 ◽

Vol 83 (3) ◽

pp. 1019-1029 ◽

Cited By ~ 21

Author(s):

Julienne C. Kaiser ◽

Sameha Omer ◽

Jessica R. Sheldon ◽

Ian Welch ◽

David E. Heinrichs

Keyword(s):

Staphylococcus Aureus ◽

Virulence Gene ◽

Defined Medium ◽

Infection Model ◽

Content Type ◽

Virulence Gene Expression ◽

Branched Chain Amino Acid ◽

Branched Chain

The branched-chain amino acids (BCAAs; Ile, Leu, and Val) not only are important nutrients for the growth ofStaphylococcus aureusbut also are corepressors for CodY, which regulates virulence gene expression, implicating BCAAs as an important link between the metabolic state of the cell and virulence. BCAAs are either synthesized intracellularly or acquired from the environment.S. aureusencodes three putative BCAA transporters, designated BrnQ1, BrnQ2, and BrnQ3; their functions have not yet been formally tested. In this study, we mutated all threebrnQparalogs so as to characterize their substrate specificities and their roles in growthin vitroandin vivo. We demonstrated that in the community-associated, methicillin-resistantS. aureus(CA-MRSA) strain USA300, BrnQ1 is involved in uptake of all three BCAAs, BrnQ2 transports Ile, and BrnQ3 does not have a significant role in BCAA transport under the conditions tested. Of the three, only BrnQ1 is essential for USA300 to grow in a chemically defined medium that is limited for Leu or Val. Interestingly, we observed that abrnQ2mutant grew better than USA300 in media limited for Leu and Val, owing to the fact that this mutation leads to overexpression ofbrnQ1. In a murine infection model, thebrnQ1mutant was attenuated, but in contrast,brnQ2mutants had significantly increased virulence compared to that of USA300, a phenotype we suggest is at least partially linked to enhancedin vivoscavenging of Leu and Val through BrnQ1. These data uncover a hitherto-undiscovered connection between nutrient acquisition and virulence in CA-MRSA.

Download Full-text

Pharmacokinetic and Pharmacodynamic Evaluation of P-873 versus Klebsiella pneumoniae in a Neutropenic Murine Thigh Infection Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02170-12 ◽

2013 ◽

Vol 57 (4) ◽

pp. 1971-1973 ◽

Cited By ~ 3

Author(s):

Lucinda M. Lamb ◽

Jared L. Crandon ◽

David P. Nicolau

Keyword(s):

Protein Synthesis ◽

Klebsiella Pneumoniae ◽

Infection Model ◽

Protein Synthesis Inhibitors ◽

Content Type ◽

Pharmacokinetic Properties

ABSTRACTP-873 is a novel compound in the RX-04 pyrrolocytosine series of protein synthesis inhibitors currently under development by Rib-X Pharmaceuticals. We evaluated the pharmacodynamic and pharmacokinetic properties of this compound againstKlebsiella pneumoniaeusing a murine neutropenic thigh infection model. P-873 demonstrated potent and rapidin vivoactivity against this organism with enhanced penetration and duration of exposure in thigh tissue.

Download Full-text

Activity of the Pore-Forming Virulence Factor Listeriolysin O Is Reversibly Inhibited by Naturally Occurring S-Glutathionylation

Infection and Immunity ◽

10.1128/iai.00959-16 ◽

2017 ◽

Vol 85 (4) ◽

Cited By ~ 15

Author(s):

Jonathan L. Portman ◽

Qiongying Huang ◽

Michelle L. Reniere ◽

Anthony T. Iavarone ◽

Daniel A. Portnoy

Keyword(s):

Protein Function ◽

Inhibitory Effect ◽

Cysteine Residue ◽

Infection Model ◽

Listeriolysin O ◽

Content Type ◽

Pore Forming Proteins

ABSTRACT Cholesterol-dependent cytolysins (CDCs) represent a family of homologous pore-forming proteins secreted by many Gram-positive bacterial pathogens. CDCs mediate membrane binding partly through a conserved C-terminal undecapeptide, which contains a single cysteine residue. While mutational changes to other residues in the undecapeptide typically have severe effects, mutation of the cysteine residue to alanine has minor effects on overall protein function. Thus, the role of this highly conserved reactive cysteine residue remains largely unknown. We report here that the CDC listeriolysin O (LLO), secreted by the facultative intracellular pathogen Listeria monocytogenes, was posttranslationally modified by S-glutathionylation at this conserved cysteine residue and that either endogenously synthesized or exogenously added glutathione was sufficient to form this modification. When recapitulated with purified protein in vitro, this modification completely ablated the activity of LLO, and this inhibitory effect was fully reversible by treatment with reducing agents. A cysteine-to-alanine mutation in LLO rendered the protein completely resistant to inactivation by S-glutathionylation, and a mutant expressing this mutation retained full hemolytic activity. A mutant strain of L. monocytogenes expressing the cysteine-to-alanine variant of LLO was able to infect and replicate within bone marrow-derived macrophages indistinguishably from the wild type in vitro, yet it was attenuated 4- to 6-fold in a competitive murine infection model in vivo. This study suggests that S-glutathionylation may represent a mechanism by which CDC-family proteins are posttranslationally modified and regulated and help explain an evolutionary pressure to retain the highly conserved undecapeptide cysteine.

Download Full-text