An isolated CLASP TOG domain suppresses microtubule catastrophe and promotes rescue

Microtubules are heavily regulated dynamic polymers of αβ-tubulin that are required for proper chromosome segregation and organization of the cytoplasm. Polymerases in the XMAP215 family use arrayed TOG domains to promote faster microtubule elongation. Regulatory factors in the cytoplasmic linker associated protein (CLASP) family that reduce catastrophe and/or increase rescue also contain arrayed TOGs, but how CLASP TOGs contribute to activity is poorly understood. Here, using Saccharomyces cerevisiae Stu1 as a model CLASP, we report structural, biochemical, and reconstitution studies that clarify functional properties of CLASP TOGs. The two TOGs in Stu1 have very different tubulin-binding properties: TOG2 binds to both unpolymerized and polymerized tubulin, and TOG1 binds very weakly to either. The structure of Stu1-TOG2 reveals a CLASP-specific residue that likely confers distinctive tubulin-binding properties. The isolated TOG2 domain strongly suppresses microtubule catastrophe and increases microtubule rescue in vitro, contradicting the expectation that regulatory activity requires an array of TOGs. Single point mutations on the tubulin-binding surface of TOG2 ablate its anti-catastrophe and rescue activity in vitro, and Stu1 function in cells. Revealing that an isolated CLASP TOG can regulate polymerization dynamics without being part of an array provides insight into the mechanism of CLASPs and diversifies the understanding of TOG function.

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Mutation of the Zinc-Binding Metalloprotease Motif Affects Bacteroides fragilis Toxin Activity but Does Not Affect Propeptide Processing

Infection and Immunity ◽

10.1128/iai.73.8.5273-5277.2005 ◽

2005 ◽

Vol 73 (8) ◽

pp. 5273-5277 ◽

Cited By ~ 21

Author(s):

Augusto A. Franco ◽

Simy L. Buckwold ◽

Jai W. Shin ◽

Miguel Ascon ◽

Cynthia L. Sears

Keyword(s):

Single Point ◽

Point Mutations ◽

Bacteroides Fragilis ◽

Site Directed Mutagenesis ◽

Zinc Binding ◽

Consensus Sequences ◽

Biologic Activity ◽

Single Point Mutations

ABSTRACT To evaluate the role of the zinc-binding metalloprotease in Bacteroides fragilis toxin (BFT) processing and activity, the zinc-binding consensus sequences (H348, E349, H352, G355, H358, and M366) were mutated by site-directed-mutagenesis. Our results indicated that single point mutations in the zinc-binding metalloprotease motif do not affect BFT processing but do reduce or eliminate BFT biologic activity in vitro.

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Regulation of Virus Neutralization and the Persistent Fraction by TRIM21

Journal of Virology ◽

10.1128/jvi.00728-12 ◽

2012 ◽

Vol 86 (16) ◽

pp. 8482-8491 ◽

Cited By ~ 53

Author(s):

W. A. McEwan ◽

F. Hauler ◽

C. R. Williams ◽

S. R. Bidgood ◽

D. L. Mallery ◽

...

Keyword(s):

Single Point ◽

Point Mutations ◽

Direct Interaction ◽

Neutralizing Antibody ◽

Adenovirus Type ◽

Antibody Neutralization ◽

Human Virus ◽

Single Point Mutations ◽

Adenovirus Type 5 ◽

Insight Into

Despite a central role in immunity, antibody neutralization of virus infection is poorly understood. Here we show how the neutralization and persistence of adenovirus type 5, a prevalent nonenveloped human virus, are dependent upon the intracellular antibody receptor TRIM21. Cells with insufficient amounts of TRIM21 are readily infected, even at saturating concentrations of neutralizing antibody. Conversely, high TRIM21 expression levels decrease the persistent fraction of the infecting virus and allows neutralization by as few as 1.6 antibody molecules per virus. The direct interaction between TRIM21 and neutralizing antibody is essential, as single-point mutations within the TRIM21-binding site in the Fc region of a potently neutralizing antibody impair neutralization. However, infection at high multiplicity can saturate TRIM21 and overcome neutralization. These results provide insight into the mechanism and importance of a newly discovered, effector-driven process of antibody neutralization of nonenveloped viruses.

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gyrA Mutations in Ciprofloxacin-Resistant Bartonella bacilliformis Strains Obtained In Vitro

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.383-386.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 383-386 ◽

Cited By ~ 20

Author(s):

Michael F. Minnick ◽

Zachary R. Wilson ◽

Laura S. Smitherman ◽

D. Scott Samuels

Keyword(s):

Single Point ◽

Point Mutations ◽

Dna Gyrase ◽

Wild Type ◽

Bartonella Bacilliformis ◽

E Coli ◽

A Subunit ◽

Resistant Strains ◽

Single Point Mutations

ABSTRACT We isolated and characterized mutants of Bartonella bacilliformis that are resistant to the fluoroquinolone antibiotic ciprofloxacin, which targets the A subunit of DNA gyrase. Mutants had single point mutations in the gyrA gene that changed either Asp-90 to Gly or Asp-95 to Asn and had 3- or 16-fold higher resistance, respectively, to ciprofloxacin than did wild-type B. bacilliformis. Asp-95 is homologous to Asp-87 of Escherichia coli GyrA and is a common residue mutated in fluoroquinolone-resistant strains of other bacteria. This is the first report of a mutation at an Asp-90 homologue, which corresponds to Asp-82 in E. coli GyrA.

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Cupin Variants as Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

10.26434/chemrxiv.11481834.v1 ◽

2019 ◽

Author(s):

Nobutaka Fujieda ◽

Miho Yuasa ◽

Yosuke Nishikawa ◽

Genji Kurisu ◽

Shinobu Itoh ◽

...

Keyword(s):

Michael Addition ◽

In Silico ◽

Addition Reaction ◽

Single Point ◽

Point Mutations ◽

Unsaturated Ketone ◽

Michael Addition Reaction ◽

Beta Barrel ◽

Cupin Superfamily ◽

Single Point Mutations

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.

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Single-Point Mutations in Qβ Virus-like Particles Change Binding to Cells

Biomacromolecules ◽

10.1021/acs.biomac.1c00443 ◽

2021 ◽

Author(s):

Marisa L. Martino ◽

Stephen N. Crooke ◽

Marianne Manchester ◽

M.G. Finn

Keyword(s):

Single Point ◽

Point Mutations ◽

Virus Like Particles ◽

Single Point Mutations

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MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

Biochemical Journal ◽

10.1042/bcj20170357 ◽

2017 ◽

Vol 474 (18) ◽

pp. 3189-3205 ◽

Cited By ~ 6

Author(s):

Ashoka Chary Taviti ◽

Tushar Kant Beuria

Keyword(s):

Cell Division ◽

Single Point ◽

Point Mutations ◽

Direct Interaction ◽

Ring Formation ◽

Z Ring ◽

Single Point Mutations ◽

Biochemical Analyses ◽

Ftsz Assembly ◽

The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

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