PDBsum entry 2m99

Hydrolase inhibitor

PDB id: 2m99

Contents

Protein chain

57 a.a.

PDB id:

2m99

Name:

Hydrolase inhibitor

Title:

Solution structure of a chymotrypsin inhibitor from the taiwan cobra

Structure:

Protease inhibitor naci. Chain: a. Synonym: chymotrypsin inhibitor, naci. Engineered: yes

Source:

Naja atra. Taiwan cobra. Organism_taxid: 8656. Gene: aci. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

20 models

Authors:

Y.-J.Lin,T.Ikeya,P.Guntert,L.-S.Chang

Key ref:

Y.J.Lin et al. (2013). NMR solution structure of a Chymotrypsin inhibitor from the Taiwan cobra Naja naja atra. Molecules, 18, 8906-8918. PubMed id: 23896616 DOI: 10.3390/molecules18088906

Date:

05-Jun-13 Release date: 16-Oct-13

Protein chain

Q5ZPJ7  (VKT_NAJAT) -  Kunitz-type serine protease inhibitor NACI from Naja atra

Seq: 81 a.a.

Struc: 57 a.a.

DOI no: 10.3390/molecules18088906

Molecules 18:8906-8918 (2013)

PubMed id: 23896616

NMR solution structure of a Chymotrypsin inhibitor from the Taiwan cobra Naja naja atra.

Y.J.Lin, T.Ikeya, P.Güntert, L.S.Chang.

ABSTRACT

The Taiwan cobra (Naja naja atra) chymotrypsin inhibitor (NACI) consists of 57 amino acids and is related to other Kunitz-type inhibitors such as bovine pancreatic trypsin inhibitor (BPTI) and Bungarus fasciatus fraction IX (BF9), another chymotrypsin inhibitor. Here we present the solution structure of NACI. We determined the NMR structure of NACI with a root-mean-square deviation of 0.37 Å for the backbone atoms and 0.73 Å for the heavy atoms on the basis of 1,075 upper distance limits derived from NOE peaks measured in its NOESY spectra. To investigate the structural characteristics of NACI, we compared the three-dimensional structure of NACI with BPTI and BF9. The structure of the NACI protein comprises one 310-helix, one α-helix and one double-stranded antiparallel β-sheet, which is comparable with the secondary structures in BPTI and BF9. The RMSD value between the mean structures is 1.09 Å between NACI and BPTI and 1.27 Å between NACI and BF9. In addition to similar secondary and tertiary structure, NACI might possess similar types of protein conformational fluctuations as reported in BPTI, such as Cys14-Cys38 disulfide bond isomerization, based on line broadening of resonances from residues which are mainly confined to a region around the Cys14-Cys38 disulfide bond.