1IB9: Mcoti-II, a macrocyclic trypsin inhibitor

Solution structure of mcoti-II, a macrocyclic trypsin inhibitor. Determined by solution NMR. Released 18 Jul 2001.

Method: Solution NMR
Organism: Momordica cochinchinensis
Chains: 1
Atoms: 236
Mol. weight: 3.48 kDa
Released: 18 Jul 2001

Explore 1IB9 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1IB9 contains 1 α-helix and 4 β-strands across 1 chain. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 1 helix, 4 β-strands

Element	Residues	Length	Sheet
β-strand	14	1	1
α-helix	18-20	3
β-strand	27	1	2
β-strand	32	1	1
β-strand	33	1	2

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Trypsin inhibitor II	A	protein	34	Momordica cochinchinensis	P82409 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>1IB9_1 TRYPSIN INHIBITOR II (chains A)
SGSDGGVCPKILKKCRRDSDCPGACICRGNGYCG

Primary citation

Circular proteins in plants: solution structure of a novel macrocyclic trypsin inhibitor from Momordica cochinchinensis. Felizmenio-Quimio, M.E., Daly, N.L., Craik, D.J. J Biol Chem (2001) 276:22875-22882. DOI 10.1074/jbc.M101666200 · PubMed

Other PDB entries of the same protein (UniProt P82409 (AlphaFold model), which also has an AlphaFold model), best resolution first:

2C4B 1.3 Å, Inhibitor cystine knot protein McoEeTI fused to the catalytically inactive barnase…
4GUX 1.8 Å, Crystal structure of trypsin:MCoTi-II complex
1HA9 Solution structure of the squash trypsin inhibitor mcoti-II, NMR, 30 structures.
2IT8 Solution structure of a linear analog of the cyclic squash trypsin inhibitor MCoTI-II
2MT8 Solution structure MTAbl13, a grafted MCoTI-II
2PO8 The structure of a two-disulfide intermediate of MCoTI-II

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