PDBsum entry 2tld

Hydrolase/hydrolase inhibitor

PDB id: 2tld

Contents

Protein chains

220 a.a.* *

110 a.a.* *

* Residue conservation analysis

* C-alpha coords only

PDB id:

2tld

Name:

Hydrolase/hydrolase inhibitor

Title:

Crystal structure of an engineered subtilisin inhibitor complexed with bovine trypsin

Structure:

Trypsin. Chain: e. Engineered: yes. Streptomyces subtilisin inhibitor (ssi). Chain: i. Engineered: yes

Source:

Bos taurus. Cattle. Organism_taxid: 9913.

Resolution:

2.60Å R-factor: 0.173

Authors:

Y.Mitsui,Y.Takeuchi,T.Nonaka,K.T.Nakamura

Key ref:

Y.Takeuchi et al. (1992). Crystal structure of an engineered subtilisin inhibitor complexed with bovine trypsin. Proc Natl Acad Sci U S A, 89, 4407-4411. PubMed id: 1584773 DOI: 10.1073/pnas.89.10.4407

Date:

16-Sep-91 Release date: 15-Jul-92

Protein chain

P00760  (TRY1_BOVIN) -  Serine protease 1 from Bos taurus

Seq: 246 a.a.

Struc: 220 a.a.

Protein chain

P01006  (SSI_STRAO) -  Subtilisin inhibitor from Streptomyces albogriseolus

Seq: 144 a.a.

Struc: 110 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class 2: Chain E: E.C.3.4.21.4 - trypsin.
• Reaction: Preferential cleavage: Arg-|-Xaa, Lys-|-Xaa.
• Enzyme class 3: Chain I: E.C.?

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

DOI no: 10.1073/pnas.89.10.4407

Proc Natl Acad Sci U S A 89:4407-4411 (1992)

PubMed id: 1584773

Crystal structure of an engineered subtilisin inhibitor complexed with bovine trypsin.

Y.Takeuchi, T.Nonaka, K.T.Nakamura, S.Kojima, K.Miura, Y.Mitsui.

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.