PDBsum entry: 1ta3

Hydrolase inhibitor/hydrolase

PDB id: 1ta3

Contents

Protein chains

274 a.a. *

301 a.a. *

Ligands

NAG ×2

EDO ×7

Waters ×785

* Residue conservation analysis

PDB id:

1ta3

Name:

Hydrolase inhibitor/hydrolase

Title:

Crystal structure of xylanase (gh10) in complex with inhibit

Structure:

Xylanase inhibitor protein i. Chain: a. Synonym: xip-1. Endo-1,4-beta-xylanase. Chain: b. Synonym: gh10, 34 kda xylanase, 1,4-beta-d-xylan xylanohydr x34. Engineered: yes

Source:

Triticum aestivum. Bread wheat. Organism_taxid: 4565. Emericella nidulans. Organism_taxid: 162425. Gene: xlnc. Expressed in: emericella nidulans. Expression_system_taxid: 162425

Biol. unit:

Dimer (from PQS)

Resolution:

1.70Å R-factor: 0.135 R-free: 0.166

Authors:

F.Payan,P.Leone,C.Furniss,T.Tahir,A.Durand,S.Porciero,P.Manz G.Williamson,H.J.Gilbert,N.Juge,A.Roussel

Key ref:

F.Payan et al. (2004). The dual nature of the wheat xylanase protein inhibitor XIP-I: structural basis for the inhibition of family 10 and family 11 xylanases. J Biol Chem, 279, 36029-36037. PubMed id: 15181003 DOI: 10.1074/jbc.M404225200

Date:

19-May-04 Release date: 20-Jul-04

Protein chain

Q8L5C6  (XIP1_WHEAT) -  Xylanase inhibitor protein 1

Seq: 304 a.a.

Struc: 274 a.a.

Protein chain

Q00177  (XYNC_EMENI) -  Endo-1,4-beta-xylanase C

Seq: 327 a.a.

Struc: 301 a.a.

Enzyme reactions

• Enzyme class: Chain B: E.C.3.2.1.8 - Endo-1,4-beta-xylanase.
• Reaction: Endohydrolysis of 1,4-beta-D-xylosidic linkages in xylans.

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (1 term)
• Biological process: metabolic process (4 terms)
• Biochemical function: catalytic activity (6 terms)

DOI no: 10.1074/jbc.M404225200

J Biol Chem 279:36029-36037 (2004)

PubMed id: 15181003

The dual nature of the wheat xylanase protein inhibitor XIP-I: structural basis for the inhibition of family 10 and family 11 xylanases.

F.Payan, P.Leone, S.Porciero, C.Furniss, T.Tahir, G.Williamson, A.Durand, P.Manzanares, H.J.Gilbert, N.Juge, A.Roussel.

ABSTRACT

The xylanase inhibitor protein I (XIP-I) from wheat Triticum aestivum is the prototype of a novel class of cereal protein inhibitors that inhibit fungal xylanases belonging to glycoside hydrolase families 10 (GH10) and 11 (GH11). The crystal structures of XIP-I in complex with Aspergillus nidulans (GH10) and Penicillium funiculosum (GH11) xylanases have been solved at 1.7 and 2.5 A resolution, respectively. The inhibition strategy is novel because XIP-I possesses two independent enzyme-binding sites, allowing binding to two glycoside hydrolases that display a different fold. Inhibition of the GH11 xylanase is mediated by the insertion of an XIP-I Pi-shaped loop (Lalpha(4)beta(5)) into the enzyme active site, whereas residues in the helix alpha7 of XIP-I, pointing into the four central active site subsites, are mainly responsible for the reversible inactivation of GH10 xylanases. The XIP-I strategy for inhibition of xylanases involves substrate-mimetic contacts and interactions occluding the active site. The structural determinants of XIP-I specificity demonstrate that the inhibitor is able to interact with GH10 and GH11 xylanases of both fungal and bacterial origin. The biological role of the xylanase inhibitors is discussed in light of the present structural data.

Selected figure(s)

Figure 1.
FIG. 1. A, structure of the XIP-I-XLNC complex. XIP-I is in red and blue, and A. nidulans xylanase (XLNC) is in purple and green. The main interaction residues are shown in a stick representation, Lys-234[XIP-I] side chain (dark blue) is important for the interaction with XLNC, and Arg-149[XIP-I] (light blue) is important for the interaction with XYNC (B), together with the side chains of the two catalytic residues (red). B, structure of the XIP-I-XYNC complex. XIP-I is in red and blue, and P. funiculosum xylanase (XYNC) is in purple and green. The long inhibitor loop interacting directly in the xylanase active site is shown. The main interaction residues are shown in a stick representation, Arg-149[XIP-I] side chain (dark blue) is important for the interaction with XYNC, and Lys-234[XIP-I] (light blue) is important for the interaction with XLNC (see A), together with the side chains of the two catalytic residues (red). Figures were generated by SPOCK (36).

Figure 2.
FIG. 2. A, structural basis for the inhibition of GH10 xylanase XLNC. The molecular surface of XLNC is shown in gray. Enzyme surfaces (and corresponding residues numbering) interacting with XIP-I are depicted in purple, blue, and green. The known substrate subsites are labeled. Inhibitor residues interacting in the active site groove are shown in a stick representation (colored according to the atom type). Regions from the inhibitor molecule involved in the inhibiting mechanism are represented by red tubes (residue numbering in parentheses). B, structural basis for the inhibition of GH11 xylanase XYNC. A close up of the XYNC active site is the same as in A. Figures were prepared with SPOCK (36).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 36029-36037) copyright 2004.

Figures were selected by an automated process.