1BE6: TRANS-CINNAMOYL-SUBTILISIN IN ANHYDROUS ACETONITRILE

Citation:
Abstract
The x-ray crystal structures of trans-cinnamoyl-subtilisin, an acyl-enzyme covalent intermediate of the serine protease subtilisin Carlsberg, have been determined to 2.2-A resolution in anhydrous acetonitrile and in water. The cinnamoyl-subtilisin structures are virtually identical in the two solvents. In addition, their enzyme portions are nearly indistinguishable from previously determined structures of the free enzyme in acetonitrile and in water; thus, acylation in either aqueous or nonaqueous solvent causes no appreciable conformational changes. However, the locations of bound solvent molecules in the active site of the acyl- and free enzyme forms in acetonitrile and in water are distinct. Such differences in the active site solvation may contribute to the observed variations in enzymatic activities. On prolonged exposure to organic solvent or removal of interstitial solvent from the crystal lattice, the channels within enzyme crystals are shown to collapse, leading to a drop in the number of active sites accessible to the substrate. The mechanistic and preparative implications of our findings for enzymatic catalysis in organic solvents are discussed.
PDB ID: 1BE6Download
MMDB ID: 55496
PDB Deposition Date: 1998/5/20
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2.15  Å
Source Organism:
Similar Structures:
Biological Unit for 1BE6: monomeric; determined by author
Molecular Components in 1BE6
Label Count Molecule
Protein (1 molecule)
1
Subtilisin Carlsberg
Molecule annotation
Chemicals (14 molecules)
1
1
2
1
3
12
* Click molecule labels to explore molecular sequence information.

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