1QH2 | pdb_00001qh2

CHYMOTRYPSIN INHIBITOR (C2) FROM NICOTIANA ALATA

• PDB DOI: https://doi.org/10.2210/pdb1QH2/pdb

• Classification: HYDROLASE INHIBITOR
• Organism(s): Nicotiana alata
• Mutation(s): No 


• Deposited: 1999-05-11 Released: 1999-05-24 
• Deposition Author(s): Lee, M.C.S., Scanlon, M.J., Anderson, M.A., Craik, D.J.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Submitted: 1 

Literature

A novel two-chain proteinase inhibitor generated by circularization of a multidomain precursor protein.

Lee, M.C., Scanlon, M.J., Craik, D.J., Anderson, M.A.

(1999) Nat Struct Biol 6: 526-530

• PubMed: 10360353 
• DOI: https://doi.org/10.1038/9293
• Primary Citation Related Structures: 
  1QH2


• PubMed Abstract: 
  

  Female reproductive tissues of the ornamental tobacco amass high levels of serine proteinase inhibitors (PIs) for protection against pests and pathogens. These PIs are produced from a precursor protein composed of six repeats each with a protease reactive site. Here we show that proteolytic processing of the precursor generates five single-chain PIs and a remarkable two-chain inhibitor formed by disulfide-bond linkage of N- and C-terminal peptide fragments. Surprisingly, PI precursors adopt this circular structure regardless of the number of inhibitor domains, suggesting this bracelet-like conformation is characteristic of the widespread potato inhibitor II (Pot II) protein family.

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Organizational Affiliation: 
• School of Biochemistry, La Trobe University, Bundoora, Victoria, Australia.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 5.02 kDa 
• Atom Count: 344 
• Modeled Residue Count: 46 
• Deposited Residue Count: 46 
• Unique protein chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN (TRYPSIN INHIBITOR C2)	A	18	Nicotiana alata	Mutation(s): 0
UniProt
Find proteins for Q40378 (Nicotiana alata) Explore Q40378  Go to UniProtKB:  Q40378

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN (TRYPSIN INHIBITOR C2)	B	28	Nicotiana alata	Mutation(s): 0
UniProt
Find proteins for Q40378 (Nicotiana alata) Explore Q40378  Go to UniProtKB:  Q40378

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Submitted: 1 

Structure Validation

Entry History 

Deposition Data

• Released Date: 1999-05-24 
Deposition Author(s): Lee, M.C.S., Scanlon, M.J., Anderson, M.A., Craik, D.J.

Revision History  

• Version 1.0: 1999-05-24
  Type: Initial release
  
• Version 1.1: 2007-10-16
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2022-03-02
  Changes: Database references, Derived calculations
• Version 1.4: 2023-12-27
  Changes: Data collection
• Version 1.5: 2024-11-13
  Changes: Structure summary