Open AccessCrystallization and preliminary X‐ray crystallographic analysis of a highly specific serpin from the beetle Tenebrio molitor
Author(s) -
Park Sun Hee,
Piao Shunfu,
Kwon HyunMi,
Kim EunHye,
Lee Bok Luel,
Ha NamChul
Publication year - 2010
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309109053147
Subject(s) - serpin , serine protease , proteases , serine , protease , masp1 , biochemistry , crystallization , biology , protein crystallization , chemistry , enzyme , gene , organic chemistry
The Toll signalling pathway, which is crucial for innate immunity, is transduced in insect haemolymph via a proteolytic cascade consisting of three serine proteases. The proteolytic cascade is downregulated by a specific serine protease inhibitor (serpin). Recently, the serpin SPN48 was found to show an unusual specific reactivity towards the terminal serine protease, Spätzle‐processing enzyme, in the beetle Tenebrio molitor . In this study, the mature form of SPN48 was overexpressed in Escherichia coli and purified. The purified SPN48 protein was crystallized using 14% polyethylene glycol 8000 and 0.1 M 2‐( N ‐morpholino)ethanesulfonic acid pH 6.0 as the precipitant. The crystals diffracted X‐rays to 2.1 Å resolution and were suitable for structure determination. The crystals belonged to space group P 2 1 . The crystal structure will provide information regarding how SPN48 achieves its unusual specificity for its target protease.