PDBsum entry 4xoj

Hydrolase

PDB id: 4xoj

Contents

Protein chains

223 a.a.

13 a.a.

Ligands

SO4

EDO ×7

NH4

Metals

_CA

_NA ×3

Waters ×397

References listed in PDB file

Key reference

• Title: Investigation of serine-Proteinase-Catalyzed peptide splicing in analogues of sunflower trypsin inhibitor 1 (sfti-1).
• Authors: N.Karna, A.ŁęGowska, S.Malicki, D.Dębowski, P.Golik, A.Gitlin, P.Grudnik, B.Wladyka, K.Brzozowski, G.Dubin, K.Rolka.
• Ref.: Chembiochem, 2015, 16, 2036-2045. [DOI no: 10.1002/cbic.201500296]
• PubMed id: 26212347

Abstract

Serine-proteinase-catalyzed peptide splicing was demonstrated in analogues of the trypsin inhibitor SFTI-1: both single peptides and two-peptide chains (C- and N-terminal peptide chains linked by a disulfide bridge). In the second series, peptide splicing with catalytic amount of proteinase was observed only when formation of acyl-enzyme intermediate was preceded by hydrolysis of the substrate Lys-Ser peptide bond. Here we demonstrate that with an equimolar amount of the proteinase, splicing occurs in all the two-peptide-chain analogues. This conclusion was supported by high resolution crystal structures of selected analogues in complex with trypsin. We showed that the process followed a direct transpeptidation mechanism. Thus, the acyl-enzyme intermediate was formed and was immediately used for a new peptide bond formation; products associated with the hydrolysis of the acyl-enzyme were not observed. The peptide splicing was sequence- not structure-specific.