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Publication Abstract from PubMed

The crystal structure of proteolytically modified human alpha 1-antichymotrypsin (ACT), a member of the serpin superfamily, has been solved by Paterson search techniques and refined to an R-factor of 18.0% at 2.7 A resolution with mean deviations from standard bond lengths and angles of 0.013 A and 3.1 degrees, respectively. The final model consists of 374 amino acid residues, 126 solvent molecules and five sugar residues. Asn70 could be identified unambiguously as a glycosylation site and Asn104 is probably also glycosylated. The structure of cleaved ACT is compared with cleaved alpha 1-antitrypsin (alpha 1 PI) and with plakalbumin, which are prototypical models for cleaved and intact serpins, respectively. Cleaved ACT is very similar to cleaved alpha 1 PI; in particular, it has strand s4A, which is liberated by proteolysis, inserted as the middle strand in beta-sheet A. ACT and alpha 1 PI differ locally only at sites of insertions, except at the segment s3C-turn-s4C, which is displaced by several angstrom units. This region of ACT is involved in DNA binding.

Crystal structure of cleaved human alpha 1-antichymotrypsin at 2.7 A resolution and its comparison with other serpins.,Baumann U, Huber R, Bode W, Grosse D, Lesjak M, Laurell CB J Mol Biol. 1991 Apr 5;218(3):595-606. PMID:2016749^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.