TAILIEUCHUNG - Báo cáo khoa học: Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP 16.3 and human aB-crystallin

Mycobacterium tuberculosisheat shock protein (MTB HSP ) accumulates as the dominant protein in the latent stationary phase of tuberculosis infection. MTB HSP displays several characteristics of small heat shock proteins (sHsps): its expression is increased in response to stress, it protects against protein aggregationin vitro, and it contains thecoreÔa-crystallinÕdomainfound inall sHsps. | Eur. J. Biochem. 269 1806-1813 2002 FEBS 2002 doi Functional similarities between the small heat shock proteins Mycobacterium tuberculosis HSP and human aB-crystallin Melissa M. Valdez1 John I. Clark1 2 Gabrielle J. S. Wu3 and Paul J. Muchowski4 1Departments of Biological Structure and 2 Ophthalmology University of Washington Seattle WA USA 3 Seattle Genetics Bothell WA USA 4Department of Pharmacology University of Washington Seattle WA USA Mycobacterium tuberculosis heat shock protein MTB HSP accumulates as the dominant protein in the latent stationary phase of tuberculosis infection. MTB HSP displays several characteristics of small heat shock proteins sHsps its expression is increased in response to stress it protects against protein aggregation in vitro and it contains the core a-crystallin domain found in all sHsps. In this study we characterized the chaperone activity of recombinant MTB HSP in several different assays and compared the results to those obtained with recombinant human aB-crystallin a well characterized member of the sHsp family. Recombinant MTB HSP was expressed in Escherichia coli and purified to apparent homogeneity. Similar to aB-crystallin MTB suppressed citrate synthase aggregation and in the presence of mM ATP the chaperone activity was enhanced by twofold. ATP stabilized MTB HSP against proteolysis by chymotrypsin and no effect was observed with ATPyS a nonhydrolyzable analog of ATP. Increased expression of MTB HSP resulted in protection against thermal killing in E. coli at 48 C. While the sequence similarity between human aB-crystallin and MTB HSP is only 18 these results suggest that the functional similarities between these proteins containing the core a-crystallin domain are much closer. Keywords ATP human aB-crystallin molecular chaperone Mycobacterium tuberculosis HSP small heat shock proteins. One-third of the world s population is .

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• Report medicine
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• cytoplasm
• analysis of cytoplasmic
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• bacteria
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