Identification of bis-ANS binding sites in Mycobacterium tuberculosis small heat shock protein Hsp16.3: Evidences for a two-step substrate-binding mechanism

2006 ◽  
Vol 349 (1) ◽  
pp. 167-171 ◽  
Author(s):  
Xinmiao Fu ◽  
Zengyi Chang
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Binding Sites ◽  
Substrate Binding ◽  
Small Heat Shock Protein ◽  
Binding Mechanism ◽  
Ans Binding

scholarly journals Small Heat Shock Protein IbpB Acts as a Robust Chaperone in Living Cells by Hierarchically Activating Its Multi-type Substrate-binding Residues

2013 ◽  
Vol 288 (17) ◽  
pp. 11897-11906 ◽  
Author(s):  
Xinmiao Fu ◽  
Xiaodong Shi ◽  
Linxiang Yin ◽  
Jiafeng Liu ◽  
Keehyoung Joo ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Substrate Binding ◽  
Small Heat Shock Protein ◽  
Living Cells ◽  
Binding Residues

scholarly journals Dodecameric structure of the small heat shock protein Acr1 from Mycobacterium tuberculosis. VOLUME 280 (2005) PAGES 33419-33425

2005 ◽  
Vol 280 (46) ◽  
pp. 38888
Author(s):  
Christopher K. Kennaway ◽  
Justin L.P. Benesch ◽  
Ulrich Gohlke ◽  
Luchun Wang ◽  
Carol V. Robinson ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Small Heat Shock Protein

scholarly journals Substrate binding site flexibility of the small heat shock protein molecular chaperones

2009 ◽  
Vol 106 (37) ◽  
pp. 15604-15609 ◽  
Author(s):  
Nomalie Jaya ◽  
Victor Garcia ◽  
Elizabeth Vierling
Keyword(s):  
Heat Shock ◽  
Binding Sites ◽  
Cell Damage ◽  
Substrate Binding ◽  
Direct Interaction ◽  
Variable Region ◽  
Small Heat Shock Protein ◽  
Inherited Disease ◽  
Intrinsically Disordered ◽  
Interaction Sites

Small heat shock proteins (sHSPs) serve as a first line of defense against stress-induced cell damage by binding and maintaining denaturing proteins in a folding-competent state. In contrast to the well-defined substrate binding regions of ATP-dependent chaperones, interactions between sHSPs and substrates are poorly understood. Defining substrate-binding sites of sHSPs is key to understanding their cellular functions and to harnessing their aggregation-prevention properties for controlling damage due to stress and disease. We incorporated a photoactivatable cross-linker at 32 positions throughout a well-characterized sHSP, dodecameric PsHsp18.1 from pea, and identified direct interaction sites between sHSPs and substrates. Model substrates firefly luciferase and malate dehydrogenase form strong contacts with multiple residues in the sHSP N-terminal arm, demonstrating the importance of this flexible and evolutionary variable region in substrate binding. Within the conserved α-crystallin domain both substrates also bind the β-strand (β7) where mutations in human homologs result in inherited disease. Notably, these binding sites are poorly accessible in the sHSP atomic structure, consistent with major structural rearrangements being required for substrate binding. Detectable differences in the pattern of cross-linking intensity of the two substrates and the fact that substrates make contacts throughout the sHSP indicate that there is not a discrete substrate binding surface. Our results support a model in which the intrinsically-disordered N-terminal arm can present diverse geometries of interaction sites, which is likely critical for the ability of sHSPs to protect efficiently many different substrates.

The reassembling process of the nonameric Mycobacterium tuberculosis small heat-shock protein Hsp16.3 occurs via a stepwise mechanism

2002 ◽  
Vol 363 (2) ◽  
pp. 329-334 ◽  
Author(s):  
Xiuguang FENG ◽  
Sufang HUANG ◽  
Xinmiao FU ◽  
Abuduaini ABULIMITI ◽  
Zengyi CHANG
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Quaternary Structure ◽  
Small Heat Shock Protein ◽  
Oligomeric Proteins ◽  
Stepwise Mechanism ◽  
Pore Gradient ◽  
Modified Urea

Conditions are reported under which the reassembled intermediates of the heat-shock protein Hsp16.3 after being denatured in 8M urea were detected by mainly using urea-gradient PAGE (with modifications) and urea-denaturing pore-gradient PAGE. Hsp16.3 is the small heat-shock protein from Mycobacterium tuberculosis, which exists as a specific nonamer and was proposed to form a trimer-of-trimers structure. The refolding and reassembling of this protein was achieved rapidly by dilution or dialysis, suggesting an effectively spontaneous recovery of quaternary structure. Data presented in this report demonstrate that the in vitro reassembling process of Hsp16.3 protein occurs through a spontaneous and effective stepwise mechanism. Modified urea-gradient PAGE may provide a general method for studying the reassembling processes of other oligomeric proteins.

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