1Y4A

Crystal structure of the complex of subtilisin BPN' with chymotrypsin inhibitor 2 M59R/E60S mutant

Summary for 1Y4A

• Entry DOI: 10.2210/pdb1y4a/pdb
• Related: 1Y1K 1Y33 1Y34 1Y3B 1Y3C 1Y3D 1Y3F 1Y48 1Y4D
• Descriptor: subtilisin BPN', chymotrypsin inhibitor 2, CALCIUM ION, ... (7 entities in total)
• Functional Keywords: serine protease; inhibitor, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor
• Biological source: Bacillus amyloliquefaciens; More
• Cellular location: Secreted: P00782
• Total number of polymer chains: 2
• Total formula weight: 38963.81

Authors

Radisky, E.S.,Lu, C.J.,Kwan, G.,Koshland Jr., D.E. (deposition date: 2004-11-30, release date: 2005-05-17, Last modification date: 2023-08-23)

Primary citation

Radisky, E.S.,Lu, C.J.,Kwan, G.,Koshland Jr., D.E.
Role of the intramolecular hydrogen bond network in the inhibitory power of chymotrypsin inhibitor 2
Biochemistry, 44:6823-6830, 2005

PubMed Abstract: A series of mutants of chymotrypsin inhibitor 2 (CI2), at residues involved in intramolecular interactions that shape and constrain the binding loop, were studied to determine their relative importance for inhibition of the serine protease subtilisin BPN', and for resistance of the inhibitor to proteolysis. These functional properties were investigated in tandem with the crystal structures of the mutant inhibitor-enzyme complexes. A dense hydrogen bonding network that supports the binding loop in the vicinity of the scissile bond was found to be important both for enzyme affinity and for stability to proteolysis. Structural analysis, in combination with biochemical measurements, allows differentiation of the structural components most important for resistance to proteolysis and/or binding. The most critical participating residues in the network were found to be Thr-58, Glu-60, Arg-65, and Gly-83. Glu-60 is more important for resistance to proteolysis than for binding, while Arg-65 and two other Arg residues play a greater role in binding than in resistance to proteolysis. Structural comparisons reveal a wide variety of subtle conformational changes in response to mutation, with built-in robustness in the hydrogen bond network, such that loss of one contact is compensated by other new contacts.

PubMed: 15865427
DOI: 10.1021/bi047301w

Experimental method

X-RAY DIFFRACTION (1.6 Å)