PDBsum entry: 2cmy

Hydrolase

PDB id: 2cmy

Contents

Protein chains

223 a.a. *

21 a.a. *

Ligands

SO4 ×2

GOL

Metals

_CA

Waters ×110

* Residue conservation analysis

PDB id:

2cmy

Name:

Hydrolase

Title:

Crystal complex between bovine trypsin and veronica hederifolia trypsin inhibitor

Structure:

Cationic trypsin. Chain: a. Synonym: beta trypsin. Other_details: ester bond between ser 195 and inhibitor (ch residue arg15). Veronica hederifolia trypsin inhibitor. Chain: b. Other_details: ester link between arg 15 of inhibitor and s of trypsin

Source:

Bos taurus. Bovine. Organism_taxid: 9913. Organ: pancreas. Other_details: purified protein obtained from sigma. Veronica hederifolia. Ivyleaf speedwell. Organism_taxid: 202477. Tissue: seed.

Resolution:

2.25Å R-factor: 0.196 R-free: 0.253

Authors:

R.Conners,J.L.Yardley,A.Konarev,P.Shewry,R.L.Brady

Key ref:

R.Conners et al. (2007). An unusual helix-turn-helix protease inhibitory motif in a novel trypsin inhibitor from seeds of Veronica (Veronica hederifolia L.). J Biol Chem, 282, 27760-27768. PubMed id: 17640870 DOI: 10.1074/jbc.M703871200

Date:

16-May-06 Release date: 22-May-07

Protein chain

P00760  (TRY1_BOVIN) -  Cationic trypsin

Seq: 246 a.a.

Struc: 223 a.a.

Protein chain

P85981  (TI_VERHE) -  Trypsin inhibitor

Seq: 34 a.a.

Struc: 21 a.a.

Enzyme reactions

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

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (2 terms)
• Biological process: digestion (3 terms)
• Biochemical function: catalytic activity (9 terms)

DOI no: 10.1074/jbc.M703871200

J Biol Chem 282:27760-27768 (2007)

PubMed id: 17640870

An unusual helix-turn-helix protease inhibitory motif in a novel trypsin inhibitor from seeds of Veronica (Veronica hederifolia L.).

R.Conners, A.V.Konarev, J.Forsyth, A.Lovegrove, J.Marsh, T.Joseph-Horne, P.Shewry, R.L.Brady.

ABSTRACT

The storage tissues of many plants contain protease inhibitors that are believed to play an important role in defending the plant from invasion by pests and pathogens. These proteinaceous inhibitor molecules belong to a number of structurally distinct families. We describe here the isolation, purification, initial inhibitory properties, and three-dimensional structure of a novel trypsin inhibitor from seeds of Veronica hederifolia (VhTI). The VhTI peptide inhibits trypsin with a submicromolar apparent K(i) and is expected to be specific for trypsin-like serine proteases. VhTI differs dramatically in structure from all previously described families of trypsin inhibitors, consisting of a helix-turn-helix motif, with the two alpha helices tightly associated by two disulfide bonds. Unusually, the crystallized complex is in the form of a stabilized acyl-enzyme intermediate with the scissile bond of the VhTI inhibitor cleaved and the resulting N-terminal portion of the inhibitor remaining attached to the trypsin catalytic serine 195 by an ester bond. A synthetic, truncated version of the VhTI peptide has also been produced and co-crystallized with trypsin but, surprisingly, is seen to be uncleaved and consequently forms a noncovalent complex with trypsin. The VhTI peptide shows that effective enzyme inhibitors can be constructed from simple helical motifs and provides a new scaffold on which to base the design of novel serine protease inhibitors.

Selected figure(s)

Figure 1.
FIGURE 1. Isoelectric focusing of the major trypsin inhibitor fraction from seeds of V. hederifolia. The inhibitors were separated in the pH range 3–10 and then transferred to a layer of gelatin on a photographic film that was placed onto an agarose gel containing trypsin. The dark "islands" of undigested protein represent zones of inhibitory activity.

Figure 5.
FIGURE 5. Structural comparison of VhTI and other protease inhibitors. Structural alignment of a selection of trypsin-peptide inhibitor complexes highlights the differences observed in inhibitor structure. However, there is also a conserved region at the site of direct interaction with trypsin (inset). The native VhTI structure is shown in red, synthetic VhTI is in black, 1AN1 is in cyan, 1BZX is in blue, 1C9P is in green, 1F2S is in light green, 1OX1 is in gray, 1SBW is in salmon, 1TX6 is in violet, 1TAW is in light blue, 1TFX is in yellow, and 1SFI is in orange.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 27760-27768) copyright 2007.

Figures were selected by the author.