Biological Assembly 1  

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 6397.06 
• Atom Count: 446 
• Residue Count: 57 
• Unique protein chains: 1

2M99

Solution structure of a chymotrypsin inhibitor from the Taiwan cobra

• DOI: 10.2210/pdb2M99/pdb
• BMRB: 19287

• Classification: HYDROLASE INHIBITOR
• Organism(s): Naja atra
• Expression System: Escherichia coli


• Deposited: 2013-06-05 Released: 2013-10-16 
• Deposition Author(s): Lin, Y.-J., Ikeya, T., Guntert, P., Chang, L.-S.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 20 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Literature

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

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

(2013) Molecules 18: 8906-8918

• PubMed: 23896616 
• DOI: 10.3390/molecules18088906


• PubMed 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.

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Organizational Affiliation: 

Graduate Institute of Natural Products and Center of Excellence for Environmental Medicine, Kaohsiung Medical University, No.100, Shi-Chuan 1st Road, San-Ming District, Kaohsiung 807, Taiwan. [e-mail]

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Protease inhibitor NACI	A	57	Naja atra	Mutation(s): 0
Find proteins for Q5ZPJ7 (Naja atra) Go to UniProtKB:  Q5ZPJ7

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 20 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2013-06-05 
• Released Date: 2013-10-16 
• Deposition Author(s): Lin, Y.-J., Ikeya, T., Guntert, P., Chang, L.-S.

Revision History 

• Version 1.0: 2013-10-16
  Type: Initial release