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- Fodor, Krisztián, et al.
(författare)
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Extended intermolecular interactions in a serine protease-canonical inhibitor complex account for strong and highly specific inhibition.
- 2005
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Ingår i: Journal of molecular biology. - : Elsevier BV. - 0022-2836. ; 350:1, s. 156-69
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that a trypsin inhibitor from desert locust Schistocerca gregaria (SGTI) is a taxon-specific inhibitor that inhibits arthropod trypsins, such as crayfish trypsin, five orders of magnitude more effectively than mammalian trypsins. Thermal denaturation experiments, presented here, confirm the inhibition kinetics studies; upon addition of SGTI the melting temperatures of crayfish and bovine trypsins increased 27 degrees C and 4.5 degrees C, respectively. To explore the structural features responsible for this taxon specificity we crystallized natural crayfish trypsin in complex with chemically synthesized SGTI. This is the first X-ray structure of an arthropod trypsin and also the highest resolution (1.2A) structure of a trypsin-protein inhibitor complex reported so far. Structural data show that in addition to the primary binding loop, residues P3-P3' of SGTI, the interactions between SGTI and the crayfish enzyme are also extended over the P12-P4 and P4'-P5' regions. This is partly due to a structural change of region P10-P4 in the SGTI structure induced by binding of the inhibitor to crayfish trypsin. The comparison of SGTI-crayfish trypsin and SGTI-bovine trypsin complexes by structure-based calculations revealed a significant interaction energy surplus for the SGTI-crayfish trypsin complex distributed over the entire binding region. The new regions that account for stronger and more specific binding of SGTI to crayfish than to bovine trypsin offer new inhibitor sites to engineer in order to develop efficient and specific protease inhibitors for practical use.
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- Jelinek, Balazs, et al.
(författare)
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The Crystal Structure of a Trypsin-like Mutant Chymotrypsin: The Role of Position 226 in the Activity and Specificity of S189D Chymotrypsin.
- 2008
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Ingår i: Protein Journal. - 1572-3887. ; 27, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of the S189D+A226G rat chymotrypsin-B mutant has been determined at 2.2 A ° resolution. This mutant is the most trypsin-like mutant so far in the line of chymotrypsin-to-trypsin conversions, aiming for a more complete understanding of the structural basis of substrate specificity in pancreatic serine proteases. A226G caused significant rearrangements relative to S189D chymotrypsin, allowing an internal conformation of Asp189 which is close to that in trypsin. Serious distortions remain, however, in the activation domain, including zymogen-like features. The pH-profile of activity suggests that the conformation of the S1–site of the mutant is influenced also by the P1 residue of the substrate.
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