scholarly journals The Largest Open Reading Frame (pks12) in the Mycobacterium tuberculosis Genome Is Involved in Pathogenesis and Dimycocerosyl Phthiocerol Synthesis

2003 ◽  
Vol 71 (7) ◽  
pp. 3794-3801 ◽  
Author(s):  
Tatiana D. Sirakova ◽  
Vinod S. Dubey ◽  
Hwa-Jung Kim ◽  
Michael H. Cynamon ◽  
Pappachan E. Kolattukudy

ABSTRACT The cell wall lipids in Mycobacterium tuberculosis are probably involved in pathogenesis. The largest open reading frame in the genome of M. tuberculosis H37Rv, pks12, is unique in that it encodes two sets of domains needed to produce fatty acids. A pks12-disrupted mutant was produced, and disruption was confirmed by both PCR analysis and Southern blotting. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that a 430-kDa protein band present in the wild type was missing in the mutant. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MS) and liquid chromatography (LC)-MS analysis of tryptic peptides showed that 54 peptides distributed throughout this protein matched the pks12-encoded sequence. Biochemical analysis using [1-14C]propionate as the radiotracer showed that the pks12 mutant was deficient in the synthesis of dimycocerosyl phthiocerol (DIM). SDS-PAGE, immunoblot analysis of proteins, and analysis of fatty acids showed that the mutant can produce mycocerosic acids. Thus, the pks12 gene is probably involved in the synthesis of phthiocerol, the diol required for DIM synthesis. Growth of the pks12 mutant was attenuated in mouse alveolar macrophage cell line MH-S, and the virulence of the mutant in vivo was highly attenuated in a murine model. Thus, pks12 probably participates in DIM production and its expression is involved in pathogenesis.

1999 ◽  
Vol 181 (21) ◽  
pp. 6814-6821 ◽  
Author(s):  
Vanida Nopponpunth ◽  
Worachart Sirawaraporn ◽  
Patricia J. Greene ◽  
Daniel V. Santi

ABSTRACT The genes for dihydropteroate synthase of Mycobacterium tuberculosis and Mycobacterium leprae were isolated by hybridization with probes amplified from the genomic DNA libraries. DNA sequencing revealed an open reading frame of 840 bp encoding a protein of 280 amino acids for M. tuberculosisdihydropteroate synthase and an open reading frame of 852 bp encoding a protein of 284 amino acids for M. leprae dihydropteroate synthase. The dihydropteroate synthases were expressed under control of the T5 promoter in a dihydropteroate synthase-deficient strain ofEscherichia coli. Using three chromatography steps, we purified both M. tuberculosis and M. lepraedihydropteroate synthases to >98% homogeneity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed molecular masses of 29 kDa for M. tuberculosis dihydropteroate synthase and 30 kDa for M. leprae dihydropteroate synthase. Gel filtration of both enzymes showed a molecular mass of ca. 60 kDa, indicating that the native enzymes exist as dimers of two identical subunits. Steady-state kinetic parameters for dihydropteroate synthases from bothM. tuberculosis and M. leprae were determined. Representative sulfonamides and dapsone were potent inhibitors of the mycobacterial dihydropteroate synthases, but the antimycobacterial agent p-aminosalicylate, a putative dihydropteroate synthase inhibitor, was a poor inhibitor of the enzymes.


2003 ◽  
Vol 185 (7) ◽  
pp. 2112-2121 ◽  
Author(s):  
M. Ben Potters ◽  
Barbara T. Solow ◽  
Kenneth M. Bischoff ◽  
David E. Graham ◽  
Brian H. Lower ◽  
...  

ABSTRACT When soluble extracts of the extreme acidothermophilic archaeon Sulfolobus solfataricus were incubated with [γ-32P]ATP, several proteins were radiolabeled. One of the more prominent of these, which migrated with a mass of ∼46 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), was purified by column chromatography and SDS-PAGE and subjected to amino acid sequence analysis via both the Edman technique and mass spectroscopy. The best match to the partial sequence obtained was the potential polypeptide product of open reading frame sso0417, whose DNA-derived amino acid sequence displayed many features reminiscent of the 2,3-diphosphoglycerate-independent phosphoglycerate (PGA) mutases [iPGMs]. Open reading frame sso0417 was therefore cloned, and its protein product was expressed in Escherichia coli. Assays of its catalytic capabilities revealed that the protein was a moderately effective PGA mutase that also exhibited low levels of phosphohydrolase activity. PGA mutase activity was dependent upon the presence of divalent metal ions such as Co2+ or Mn2+. The recombinant protein underwent autophosphorylation when incubated with either [γ-32P]ATP or [γ-32P]GTP. The site of phosphorylation was identified as Ser59, which corresponds to the catalytically essential serine residue in bacterial and eucaryal iPGMs. The phosphoenzyme intermediate behaved in a chemically and kinetically competent manner. Incubation of the 32P-labeled phosphoenzyme with 3-PGA resulted in the disappearance of radioactive phosphate and the concomitant appearance of 32P-labeled PGA at rates comparable to those measured in steady-state assays of PGA mutase activity.


Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1377-1384 ◽  
Author(s):  
PK Schick ◽  
J Walker

The acylation of megakaryocyte proteins was studied with special emphasis on the myristoylation and palmitoylation of the glycoprotein (GP) Ib complex. Guinea pig megakaryocytes were purified and separated into subpopulations at different phases of maturation. Cells were incubated with [3H]myristate, [3H]palmitate, or [3H]acetate to study endogenous protein acylation. Cycloheximide was used to distinguish between cotranslational and posttranslational acylation and hydroxylamine to distinguish between thioester and amide linkages. After incubations, delipidated proteins or GPIb complex subunits, immunoprecipitated with PG-1, AN-51 or FMC-25 monoclonal antibody, were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and assessed by fluorography. Radiolabeled fatty acids bound to GPIX and GPIb were also analyzed by high pressure liquid chromatography (HPLC) and scintillation spectrometry. With [3H]myristic acid and [3H]acetate, GPIX was found to be a major myristoylated protein in megakaryocytes and CHRF-288 cells. Myristic acid was linked to GPIX by an amide bond, and this process occurred cotranslationally. With [3H]acetate, GPIb was primarily palmitoylated, but with [3H]myristate, GPIb was acylated with about equal mounts of myristic acid and palmitic acids. Both fatty acids were linked to GPIb by thioester bonds, and acylation was posttranslational. The myristoylation of GPIX while the palmitoylation of GPIb occurred throughout megakaryocyte maturation. Myristoylation and palmitoylation may have different functions relevant to the assembly of the GPIb complex in megakaryocytes.


1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.


Author(s):  
M Karunakaran ◽  
Vivek C Gajare ◽  
Ajoy Mandal ◽  
Mohan Mondal ◽  
S K Das ◽  
...  

This experiment was conducted to study the electrophoretic characters of heparin binding proteins (HBP) of Black Bengal buck semen and their correlation with sperm characters and cryo-survivability. Semen ejaculates (n=20/buck) were collected from nine bucks and in vitro sperm characters were evaluated at collection, after equilibration and after freeze - thawing. HBP were isolated through heparin column and discontinuous Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) was performed to assess molecular weight. Significant difference (plessthan0.01) were observed among the bucks in sperm characters and freezability. Eight protein bands of 17 to 180 kDa in seminal plasma and 7 bands in sperm were found. 180 -136 kDa HBP of seminal plasma and 134-101 kDa HBP of sperm had showed high correlation with in vitro sperm characters. Further studies on identification of these proteins and their correlation with in vivo pregnancy are needed to find their role as marker for buck selection.


1991 ◽  
Vol 11 (11) ◽  
pp. 5541-5550 ◽  
Author(s):  
J R Grove ◽  
P Banerjee ◽  
A Balasubramanyam ◽  
P J Coffer ◽  
D J Price ◽  
...  

Two classes of human cDNA encoding the insulin/mitogen-activated p70 S6 kinase have been isolated; the two classes differ only in the 5' region, such that the longer polypeptide (p70 S6 kinase alpha I; calculated Mr 58,946) consists of 525 amino acids, of which the last 502 residues are identical in sequence to the entire polypeptides encoded by the second cDNA (p70 S6 kinase alpha II; calculated Mr 56,153). Both p70 S6 kinase polypeptides predicted by these cDNAs are present in p70 S6 kinase purified from rat liver, and each is thus expressed in vivo. Moreover, both polypeptides are expressed from a single mRNA transcribed from the (longer) p70 S6 kinase alpha I cDNA through the utilization of different translational start sites. Although the two p70 S6 kinase polypeptides differ by only 23 amino acid residues, the slightly longer alpha I polypeptide exhibits anomalously slow mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), migrating at an apparent Mr of 90,000 probably because of the presence of six consecutive Arg residues immediately following the initiator methionine. Transient expression of p70 alpha I and alpha II S6 kinase cDNA in COS cells results in a 2.5- to 4-fold increase in overall S6 kinase activity. Upon immunoblotting, the recombinant p70 polypeptides appear as a closely spaced ladder of four to five bands between 65 and 70 kDa (alpha II) and 85 and 90 kDa (alpha I). Transfection with the alpha II cDNA yields only the smaller set of bands, while transfection with the alpha I cDNA generates both sets of bands. Mutation of Met-24 in the alpha I cDNA to Leu or Thr suppresses synthesis of the alpha II polypeptides. Only the p70 alpha I and alpha II polypeptides of slowest mobility on SDS-PAGE comigrate with the 70- and 90-kDa proteins observed in purified rat liver S6 kinase. Moreover, it is the recombinant p70 polypeptides of slowest mobility that coelute with S6 kinase activity on anion-exchange chromatography. The slower mobility and higher enzymatic activity of these p70 proteins is due to Ser/Thr phosphorylation, inasmuch as treatment with phosphatase 2A inactivates kinase activity and increases the mobility of the bands on SDS-PAGE in an okadaic acid-sensitive manner. Thus, the recombinant p70 S6 kinase undergoes multiple phosphorylation and partial activation in COS cells. Acquisition of S6 protein kinase catalytic function, however, is apparently restricted to the most extensively phosphorylated recombinant polypeptides.


1990 ◽  
Vol 10 (9) ◽  
pp. 4623-4629 ◽  
Author(s):  
L M Mylin ◽  
M Johnston ◽  
J E Hopper

GAL4I, GAL4II, and GAL4III are three forms of the yeast transcriptional activator protein that are readily distinguished on the basis of electrophoretic mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Phosphorylation accounts for the reduced mobility of the slowest-migrating form, GAL4III, which is found to be closely associated with high-level GAL/MEL gene expression (L. Mylin, P. Bhat, and J. Hopper, Genes Dev. 3:1157-1165, 1989). Here we show that GAL4II, like GAL4III, can be converted to GAL4I by phosphatase treatment, suggesting that in vivo GAL4II is derived from GAL4I by phosphorylation. We found that cells which overproduced GAL4 under conditions in which it drove moderate to low levels of GAL/MEL gene expression showed only forms GAL4I and GAL4II. To distinguish which forms of GAL4 (GAL4I, GAL4II, or both) might be responsible for transcription activation in the absence of GAL4III, we performed immunoblot analysis on UASgal-binding-competent GAL4 proteins from four gal4 missense mutants selected for their inability to activate transcription (M. Johnston and J. Dover, Proc. Natl. Acad. Sci. USA 84:2401-2405, 1987; Genetics 120;63-74, 1988). The three mutants with no detectable GAL1 expression did not appear to form GAL4II or GAL4III, but revertants in which GAL4-dependent transcription was restored did display GAL4II- or GAL4III-like electrophoretic species. Detection of GAL4II in a UASgal-binding mutant suggests that neither UASgal binding nor GAL/MEL gene activation is required for the formation of GAL4II. Overall, our results imply that GAL4I may be inactive in transcriptional activation, whereas GAL4II appears to be active. In light of this work, we hypothesize that phosphorylation of GAL4I makes it competent to activate transcription.


1982 ◽  
Vol 156 (6) ◽  
pp. 1739-1754 ◽  
Author(s):  
M E Medof ◽  
K Iida ◽  
C Mold ◽  
V Nussenzweig

The main finding of this paper is that CR1, the membrane receptor for C3b and C4b, together with C3b/C4b-inactivator (I), degrades C3b bound to immune complexes (C3b*). Two fragments are generated: C3c, which is released from the immune complexes, and C3d*. The C3c fragment released from the cell intermediate EAC1423b prepared with 125I-C3 was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and radioautography. It has a 135,000 mol wt and contains disulfide bonded labeled polypeptide chains of 75,000 and 31,000 mol wt, which presumably represent the beta and a fragment of the alpha-chain of C3b*. Silver staining of the SDS-PAGE gels revealed other C3-derived bands with 39-42,000 mol wt. Human erythrocytes + I also cleave C3b* into C3c and C3d*. The activity of the erythrocytes is CR1 mediated because it can be totally inhibited by monoclonal antibodies to CR1. In contrast with these results, I together with the serum protein beta 1H (H) transform EAC1423b into hemolytically inactive EAC1423bi and cleave the alpha' chain of C3b* into fragments of 70,000 and 40,000 mol wt. Small amounts of C3c are also released at relatively high concentrations of H. On a molar basis, the efficiency of CR1 in the generation of C3c and C3d is 10(4)-10(5) greater than H. An additional observation was that C3c could be released by treating EAC1423bi with CR1 + I and that this reaction was also inhibited by monoclonal antibodies to CR1. Therefore, it is likely that CR1 has binding affinity for iC3b and that the degradation of C3b* proceeds as follows: C3b (formula, see text) C3c + C3d*. Taken together, our findings argue that the processing of C3b* in vivo occurs in solid phase, that is, on the surface of cells bearing CR1.


Blood ◽  
1990 ◽  
Vol 76 (5) ◽  
pp. 887-891 ◽  
Author(s):  
BP Schick

The relationship of protein synthesis to megakaryocyte maturation has been studied in guinea pigs in vivo. Guinea pigs were injected with a single dose of [35S]methionine. Megakaryocytes and platelets were isolated daily for 4 days, and proteins from both cells were isolated by DEAE-Sephacel chromatography and analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and fluorography. All proteins in megakaryocytes corresponding to stained bands on the SDS- PAGE gels were radiolabeled at 3 hours after injection. The greatest loss of radioactivity from the megakaryocytes occurred between 1 and 3 days after injection. Only trace labeling of platelet proteins was seen at 3 hours, representing almost entirely three bands at molecular weights 47,000, 52,000, and 66,000. At 24 hours only about 13% of the maximal labeling was present, but not all proteins were labeled. The maximal labeling was at 3 days. The pattern of labeling of platelets at 3 days was identical to that of megakaryocytes at 3 hours. The protein pattern of nonmegakaryocytic marrow cells was different from that of the platelets and megakaryocytes. Data presented here suggest that most protein synthesis in megakaryocytes is completed at least 24 hours before release of the platelets to the circulation, and suggest some specificity in the proteins that are synthesized at the terminal stages of maturation.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ping Xiao ◽  
Hongzhi Huang ◽  
Xiang Li ◽  
Jianwei Chen ◽  
Jin-ao Duan

Abstract Background Radix isatidis (Isatis indigotica Fort.) is an ancient medicinal herb, which has been applied to the prevention and treatment of influenza virus since ancient times. In recent years, the antioxidant activity of Radix isatidis has been widely concerned by researchers. Our previous studies have shown that Radix isatidis protein (RIP) has good antioxidant activity in vitro. In this study, the composition of the protein was characterized and its antioxidant activity in vivo was evaluated. Methods The model of oxidative damage in mice was established by subcutaneous injection of D-galactose for 7 weeks. Commercially available kits were used to determine the content of protein and several oxidation indexes in different tissues of mice. The tissue samples were stained with hematoxylin and eosin (H&E) and the pathological changes were observed by optical microscope. The molecular weight of RIP was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The amino acid composition of RIP was determined by a non-derivative method developed by our research group. Results RIP significantly increased the activities of antioxidant enzymes such as SOD, CAT, GSH-Px and total antioxidant capability (TAOC) but decreased the MDA level in the serum, kidney and liver. H&E stained sections of liver and kidney revealed D-galactose could cause serious injury and RIP could substantially attenuate the injury. The analysis of SDS-PAGE showed that four bands with molecular weights of 19.2 kDa, 21.5 kDa, 24.8 kDa and 40.0 kDa were the main protein components of RIP. Conclusions The results suggested that RIP had excellent antioxidant activity, which could be explored as a health-care product to retard aging and a good source of protein nutrition for human consumption.


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