2TLD

CRYSTAL STRUCTURE OF AN ENGINEERED SUBTILISIN INHIBITOR COMPLEXED WITH BOVINE TRYPSIN

Summary for 2TLD

• Entry DOI: 10.2210/pdb2tld/pdb
• Related: 2SIC 3SIC
• Descriptor: TRYPSIN, STREPTOMYCES SUBTILISIN INHIBITOR (SSI) (2 entities in total)
• Functional Keywords: proteinase, hydrolase-hydrolase inhibitor complex, trypsin), hydrolase/hydrolase inhibitor
• Biological source: Bos taurus (cattle)
• Cellular location: Secreted, extracellular space: P00760; Secreted: P01006
• Total number of polymer chains: 2
• Total formula weight: 34039.29

Authors

Mitsui, Y.,Takeuchi, Y.,Nonaka, T.,Nakamura, K.T. (deposition date: 1991-09-16, release date: 1992-07-15, Last modification date: 2024-02-21)

Primary citation

Takeuchi, Y.,Nonaka, T.,Nakamura, K.T.,Kojima, S.,Miura, K.,Mitsui, Y.
Crystal structure of an engineered subtilisin inhibitor complexed with bovine trypsin.
Proc.Natl.Acad.Sci.USA, 89:4407-4411, 1992

PubMed Abstract: Proteinase specificity of a proteinaceous inhibitor of subtilisin (SSI; Streptomyces subtilisin inhibitor) can be altered so as to strongly inhibit trypsin simply by replacing P1 methionine with lysine (with or without concomitant change of the P4 residue) through site-directed mutagenesis. Now the crystal structure of one such engineered SSI (P1 methionine converted to lysine and P4 methionine converted to glycine) complexed with bovine trypsin has been solved at 2.6 A resolution and refined to a crystallographic R factor of 0.173. Comparing this structure with the previously established structure of the native SSI complexed with subtilisin BPN', it was found that (i) P1 lysine of the mutant SSI is accommodated in the S1 pocket of trypsin as usual, and (ii) upon complex formation, considerable conformation change occurs to the reactive site loop of the mutant SSI. Thus, in this case, flexibility of the reactive site loop seems important for successfully changing the proteinase specificity through mere replacement of the P1 residue.

PubMed: 1584773
DOI: 10.1073/pnas.89.10.4407

Experimental method

X-RAY DIFFRACTION (2.6 Å)