1lto
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| , resolution 2.20Å | |||||||
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| Activity: | Tryptase, with EC number 3.4.21.59 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Human alpha1-tryptase
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. 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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