2spt
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DIFFERENCES IN THE METAL ION STRUCTURE BETWEEN SR-AND CA-PROTHROMBIN FRAGMENT 1
OverviewOverview
The structure of Sr-prothrombin fragment 1 has been solved and refined by restrained least-squares methods at 2.5-A resolution to a crystallographic R value of 0.167. The protein structure is very similar to that of Ca-fragment 1. A polymeric array of five Sr2+ ions separated by about 4.0 A is buried among six gamma-carboxyglutamic acid (Gla) residues; three other Sr2+ ions interact with other Gla residues and are located further apart. One of these was not found in the Ca-fragment 1 structure. The coordination of the Sr2+ ions resembles that of Ca2+, but there are some significant differences between them. The most notable is the lack of water coordination with Sr2+ ions and two conformations for Gla 8, which change the coordination of Sr-2 and Sr-3. A hexose moiety of an oligosaccharide was located in the vicinity of Asn101 that was flexibly disordered in Ca-fragment 1. The new Sr2+ ion found may be involved in metal ion phospholipid binding interactions along with Sr-1, and Sr-7, Sr-8.
About this StructureAbout this Structure
2SPT is a Single protein structure of sequence from Bos taurus with and as ligands. Active as Thrombin, with EC number 3.4.21.5 Full crystallographic information is available from OCA.
ReferenceReference
Differences in the metal ion structure between Sr- and Ca-prothrombin fragment 1., Seshadri TP, Skrzypczak-Jankun E, Yin M, Tulinsky A, Biochemistry. 1994 Feb 8;33(5):1087-92. PMID:8110739
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