3w6m

Contribution of disulfide bond toward thermostability in hyperthermostable endocellulase

spinqualitylabelsall models 3w6m, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3w6m is a 3 chain structure with sequence from Pyrococcus horikoshii OT3. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.948Å Ligands: GOL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function O58925_PYRHO Publication Abstract from PubMed The hyperthermophilic endocellulase, EGPh (glycosyl hydrolase family 5) from Pyrococcus horikoshii possesses 4 cysteine residues forming 2 disulfide bonds, as identified by structural analysis. One of the disulfide bonds is located at the proximal region of the active site in EGPh, which exhibits a distinct pattern from that of the thermophilic endocellulase EGAc (glycosyl hydrolase family 5) of Acidothermus cellulolyticus despite the structural similarity between the two endocellulases. The structural similarity between EGPh and EGAc suggests that EGPh possesses a structure suitable for changing the position of the disulfide bond corresponding to that in EGAc. Introduction of this alternative disulfide bond in EGPh, while removing the original disulfide bond, did not result in a loss of enzymatic activity but the EGPh was no longer hyperthermostable. These results suggest that the contribution of disulfide bond to hyperthermostability at temperature higher than 100 degrees C is restrictive, and that its impact is dependent on the specific structural environment of the hyperthermophilic proteins. The data suggest that the structural position and environment of the disulfide bond has a greater effect on high-temperature thermostability of the enzyme than on the potential energy of the dihedral angle that contributes to disulfide bond cleavage. The role of disulfide bond in hyperthermophilic endocellulase.,Kim HW, Ishikawa K Extremophiles. 2013 Apr 27. PMID:23624891 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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