scholarly journals Role of exposed aromatic residues in substrate-binding of CBM family 5 chitin-binding domain of alkaline chitinase

2009 ◽  
Vol 53 (1) ◽  
pp. 311-312 ◽  
Author(s):  
F. Uni ◽  
S. Lee ◽  
R. Yatsunami ◽  
T. Fukui ◽  
S. Nakamura
Keyword(s):  
Substrate Binding ◽  
Binding Domain ◽  
Chitin Binding Domain ◽  
Aromatic Residues

scholarly journals Structural determinants for protein unfolding and translocation by the Hsp104 protein disaggregase

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Jungsoon Lee ◽  
Nuri Sung ◽  
Lythou Yeo ◽  
Changsoo Chang ◽  
Sukyeong Lee ◽  
...  
Keyword(s):  
Protein Unfolding ◽  
Substrate Binding ◽  
Binding Domain ◽  
Atp Binding ◽  
Structural Determinants ◽  
Functional Studies ◽  
Loop 2 ◽  
Loop Conformation ◽  
Do So

The ring-forming Hsp104 ATPase cooperates with Hsp70 and Hsp40 molecular chaperones to rescue stress-damaged proteins from both amorphous and amyloid-forming aggregates. The ability to do so relies upon pore loops present in the first ATP-binding domain (AAA-1; loop-1 and loop-2 ) and in the second ATP-binding domain (AAA-2; loop-3) of Hsp104, which face the protein translocating channel and couple ATP-driven changes in pore loop conformation to substrate translocation. A hallmark of loop-1 and loop-3 is an invariable and mutational sensitive aromatic amino acid (Tyr257 and Tyr662) involved in substrate binding. However, the role of conserved aliphatic residues (Lys256, Lys258, and Val663) flanking the pore loop tyrosines, and the function of loop-2 in protein disaggregation has not been investigated. Here we present the crystal structure of an N-terminal fragment of Saccharomyces cerevisiae Hsp104 exhibiting molecular interactions involving both AAA-1 pore loops, which resemble contacts with bound substrate. Corroborated by biochemical experiments and functional studies in yeast, we show that aliphatic residues flanking Tyr257 and Tyr662 are equally important for substrate interaction, and abolish Hsp104 function when mutated to glycine. Unexpectedly, we find that loop-2 is sensitive to aspartate substitutions that impair Hsp104 function and abolish protein disaggregation when loop-2 is replaced by four aspartate residues. Our observations suggest that Hsp104 pore loops have non-overlapping functions in protein disaggregation and together coordinate substrate binding, unfolding, and translocation through the Hsp104 hexamer.

Role of Chitin Binding Domain of Chitinase A ofStreptomyces cyaneusSP-27 in Protoplast Formation fromSchizophyllum commune

2009 ◽  
Vol 73 (3) ◽  
pp. 733-735 ◽  
Author(s):  
Shigekazu YANO ◽  
Arata HONDA ◽  
Nopakarn RATTANAKIT-CHANDET ◽  
Yuta NODA ◽  
Mamoru WAKAYAMA ◽  
...  
Keyword(s):  
Binding Domain ◽  
Protoplast Formation ◽  
Chitin Binding Domain ◽  
Chitinase A

Swapping the chitin-binding domain in Bacillus chitinases improves the substrate binding affinity and conformational stability

2010 ◽  
Vol 6 (8) ◽  
pp. 1492 ◽  
Author(s):  
Chilukoti Neeraja ◽  
Rajagopal Subramanyam ◽  
Bruno M. Moerschbacher ◽  
Appa Rao Podile
Keyword(s):  
Binding Affinity ◽  
Substrate Binding ◽  
Conformational Stability ◽  
Binding Domain ◽  
Chitin Binding Domain

Abstract 1055: The 70 kDa Heat Shock Cognate Protein Plays A Novel Role In Myocardial Chemokine Expression And Cardiac Dysfunction Following Ischemia And Reperfusion Injury

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Ning Zou ◽  
Lihua Ao ◽  
Xiaoping Yang ◽  
Xin Su ◽  
David A Fullerton ◽  
...  
Keyword(s):  
Heat Shock ◽  
Inflammatory Response ◽  
Cardiac Dysfunction ◽  
Substrate Binding ◽  
Binding Domain ◽  
Chemokine Expression ◽  
Heat Shock Cognate Protein ◽  
Substrate Binding Domain ◽  
Cognate Protein

Myocardial ischemia and reperfusion (I/R) causes the release of cellular proteins including heat shock proteins (HSPs). The inducible HSP70 induces cytokine production in monocytes and dendritic cells through Toll-like receptor 4 (TLR4) signaling. In evaluation of the role of HSPs in myocardial inflammatory response in a mouse heart global I/R model, we found that the 70 kDa heat shock cognate protein (HSC70), but not HSP70, was released into the extracellular space and the coronary effluent during I/R. These observations prompted us to hypothesize that HSC70 plays a novel role in postischemic myocardial inflammatory response and cardiac dysfunction. Methods: We subjected mouse hearts to global I/R (20 min/60 min) or perfusion using the Langendorff method. We examined: the effect of HSC70 antibody on myocardial chemokine expression and cardiac functional recovery following I/R, the effect of recombinant HSC70 on myocardial chemokine expression and cardiac function and the role of TLR4 and the HSC70 substrate-binding domain in the effect of HSC70 on the heart. Results: In comparison with non-immune IgG, anti-HSC70 reduced myocardial expression of KC and MCP-1 mRNAs and proteins following I/R. Moreover, treatment with anti-HSC70 improved postischemic cardiac functional recovery (66±5.4% of baseline vs. 28±5.1% of baseline in hearts treated with non-immune IgG, p<0.01). Recombinant HSC70 induced myocardial expression of KC and MCP-1 mRNAs and proteins and caused cardiac dysfunction (72±2.6% of baseline vs. 98±3.9% of baseline in perfusion controls, p<0.001) in hearts with competent TLR4 (C3H/HeN). Interestingly, these effects of HSC70 were abrogated in hearts with defective TLR4 (C3H/HeJ). The potency of HSC70 was completely lost in the absence of its substrate-binding domain. Conclusions: Taken together, our studies demonstrate, for the first time, that HSC70 plays an important role in the induction of myocardial chemokines and cardiac dysfunction during I/R. The effect of HSC70 is dependent on TLR4 and requires the presence of the substrate-binding domain. The results suggest that the release of HSC70 into the extracellular space elicits an inflammatory response and causes mechanic dysfunction in the heart.

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