PDBsum entry 1g9i

Hydrolase/hydrolase inhibitor

PDB id: 1g9i

Contents

Protein chains

223 a.a. *

22 a.a. *

Ligands

SO4 ×2

Metals

_CA

Waters ×180

* Residue conservation analysis

PDB id:

1g9i

Name:

Hydrolase/hydrolase inhibitor

Title:

Crystal structure of beta-trysin complex in cyclohexane

Structure:

Trypsinogen, cationic. Chain: e. Fragment: beta-trypsin. Bowman-birk type trypsin inhibitor. Chain: i. Synonym: artificial mung bean inhibitor. Engineered: yes

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Organ: pancreas. Synthetic: yes. Other_details: this peptide was chemically synthesized. The sequence is based on mimic bean trypsin inhibitor.

Biol. unit:

Dimer (from PQS)

Resolution:

2.20Å R-factor: 0.185 R-free: 0.243

Authors:

G.Zhu,Q.Huang,Y.Zhu,Y.Li,C.Chi,Y.Tang

Key ref:

G.Zhu et al. (2001). X-Ray study on an artificial mung bean inhibitor complex with bovine beta-trypsin in neat cyclohexane. Biochim Biophys Acta, 1546, 98. PubMed id: 11257512 DOI: 10.1016/S0167-4838(00)00299-5

Date:

24-Nov-00 Release date: 06-Dec-00

Protein chain

P00760  (TRY1_BOVIN) -  Serine protease 1 from Bos taurus

Seq: 246 a.a.

Struc: 223 a.a.

Protein chain

P01062  (IBB_VIGRR) -  Bowman-Birk type trypsin inhibitor from Vigna radiata var. radiata

Seq: 72 a.a.

Struc: 22 a.a.*

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

Enzyme reactions

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

DOI no: 10.1016/S0167-4838(00)00299-5

Biochim Biophys Acta 1546:98 (2001)

PubMed id: 11257512

X-Ray study on an artificial mung bean inhibitor complex with bovine beta-trypsin in neat cyclohexane.

G.Zhu, Q.Huang, Y.Zhu, Y.Li, C.Chi, Y.Tang.

ABSTRACT

The active trypsin inhibiting component, SPC1, was obtained during the synthesis of a 22-residue peptide with three disulfide bridges according to the mimic mung bean Bowman-Birk type inhibitor. The K(i) value of SPC1 is 1.2x10(-7) M. In order to determine the topological structure of SPC1, X-ray diffraction studies were carried out on the complex of SPC1 with bovine beta-trypsin. Only the binding loop of SPC1 resolved at 2.2 A resolution due to conformational flexibility of the other residues [1]. The amino acid sequence was re-determined and electrospray mass spectroscopy was also performed to ensure that no cleaving occurred on SPC1 and the primary sequence of SPC1 is correct. Because the protein is more rigid in nonaqueous medium as has been proved by others [2], we treated the complex of SPC1 with neat cyclohexane and then subjected it to X-ray diffraction analysis, and the result showed that all the 22 residues of SPC1 were located in the electron density map. So the topological structure of SPC1 has been determined, suggesting that crystal treatment with cyclohexane may be used as a method to determine the conformation of the disordered regions in protein crystal structures.