1lto

OverviewOverview

Human mast cell tryptases represent a subfamily of trypsin-like serine, proteinases implicated in asthma. Unlike beta-tryptases, alpha-tryptases, apparently are proteolytically inactive. We have solved the 2.2A crystal, structure of mature human alpha1-tryptase. It reveals a frame-like, tetrameric architecture that, surprisingly, does not require, heparin-binding for stability. In marked contrast to beta2-tryptase, the, Ser214-Gly219 segment, which normally provides the template for substrate, binding, is kinked in alpha-tryptase, thereby blocking its non-primed, subsites. This so far unobserved subsite distortion is incompatible with, productive substrate binding and processing. alpha-Tryptase apparently is, trapped in this off-conformation by repulsions and attractions of the, Asp216 side-chain. However, proteolytic activity could be generated by an, induced-fit mechanism.

About this StructureAbout this Structure

1LTO is a Single protein structure of sequence from Homo sapiens. Active as Tryptase, with EC number 3.4.21.59 Full crystallographic information is available from OCA.

ReferenceReference

The crystal structure of human alpha1-tryptase reveals a blocked substrate-binding region., Marquardt U, Zettl F, Huber R, Bode W, Sommerhoff C, J Mol Biol. 2002 Aug 16;321(3):491-502. PMID:12162961

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