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Title
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Amino acid sequencing of a trypsin inhibitor by refined 1.6 A X-ray crystal structure of its complex with porcine beta-trypsin.
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Authors
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Q.Huang,
S.Liu,
Y.Tang,
F.Zeng,
R.Qian.
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Ref.
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FEBS Lett, 1992,
297,
143-146.
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PubMed id
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Abstract
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The stoichiometric complex formed between porcine beta-trypsin and the Momordica
charantia, Linn. Cucurbitaceae trypsin inhibitor-A (MCTI-A) was crystallized and
its X-ray crystal structure determined using molecular replacement method. The
primary sequence and topology of the inhibitor was determined by recognizing the
electron density and refined to a final R value of 0.167 (7.0-1.6 A) with RMS
deviation of bond lengths from standard values 0.012 A. The sequence was
compared with those obtained by other groups and was found to be similar to the
squash proteinase inhibitor. Its spatial structure and the conformation of its
primary binding segment from Cys-3I (P3) to Glu-7I (P3') which contains the
reactive scissile bond Arg-5I C-Ile-6I N were also very similar with other
squash family proteinase inhibitors.
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