Interaction between xylanase and XIP-type xylanase inhibitor protein: a review

Abstract:

XIP-type xylanase inhibitor proteins have inhibitory effects on most fungal xylanases of the GH10 and GH11 families, but they cannot inhibit xylanase produced by plants and bacteria. The inhibitory effect of XIP-type xylanase inhibitor protein on xylanase is mainly through simulating substrate contacting the active site of the enzyme, and quickly blocking the channel of the substrate into the active site region. However, in the crystal structures of GH10 and GH11 xylanase that are resistant to XIP-type xylanase inhibitor proteins, the loop conformations linking secondary structures obviously hinder the inhibition of XIP-type xylanase inhibitor proteins. Compared with XIP-sensitive xylanase, the insertion mutation of amino acid residues results in a prominent conformation of the loop of resistant xylanase. In XIP-resistant GH11 xylanase, the substitution of some amino acids in the thumb structure prevents the XIP-type xylanase inhibitor protein from forming a stable hydrogen bond and hydrophobic structure with the thumb structure, thereby weakening the inhibitory effect of XIP.

Key words:Xylanase, XIP-type xylanase inhibitor protein, Molecular recognition