1n8e: Difference between revisions
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|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
|DOMAIN= | |||
|RELATEDENTRY=[[1fzc|1FZC]], [[1n86|1N86]], [[1n73|1N73]] | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1n8e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1n8e OCA], [http://www.ebi.ac.uk/pdbsum/1n8e PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1n8e RCSB]</span> | |||
}} | }} | ||
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==Overview== | ==Overview== | ||
The crystal structure of fragment double-D from factor XIII-cross-linked lamprey fibrin has been determined at 2.9 A resolution. The 180 kDa covalent dimer was cocrystallized with the peptide Gly-His-Arg-Pro-amide, which in many fibrinogens, but not that of lamprey, corresponds to the B-knob exposed by thrombin. The structure was determined by molecular replacement, a recently determined structure of lamprey fragment D being used as a search model. GHRPam was found in both the gamma- and beta-chain holes. Unlike the situation with fragment D, the crystal packing of the cross-linked double-D structure exhibits two different D-D interfaces, each gamma-chain facing gamma-chains on two other molecules. One of these (interface I) involves the asymmetric interface observed in all other D fragments and related structures. The other (interface II) encompasses a completely different set of residues. The two abutments differ in that interface I results in an "in line" arrangement of abutting molecules and the interface II in a "zigzag" arrangement. So far as can be determined (the electron density could only be traced on one side of the cross-links), it is the gamma-chains of the newly observed zigzag units (interface II) that are joined by the reciprocal epsilon-amino-gamma-glutamyl cross-links. Auspiciously, the same novel D-D interface was observed in two lower-resolution crystal structures of human double-D preparations that had been crystallized under unusual circumstances. These observations show that double-D structures are linked in a way that is sufficiently flexible to accommodate different D-D interfaces under different circumstances. | The crystal structure of fragment double-D from factor XIII-cross-linked lamprey fibrin has been determined at 2.9 A resolution. The 180 kDa covalent dimer was cocrystallized with the peptide Gly-His-Arg-Pro-amide, which in many fibrinogens, but not that of lamprey, corresponds to the B-knob exposed by thrombin. The structure was determined by molecular replacement, a recently determined structure of lamprey fragment D being used as a search model. GHRPam was found in both the gamma- and beta-chain holes. Unlike the situation with fragment D, the crystal packing of the cross-linked double-D structure exhibits two different D-D interfaces, each gamma-chain facing gamma-chains on two other molecules. One of these (interface I) involves the asymmetric interface observed in all other D fragments and related structures. The other (interface II) encompasses a completely different set of residues. The two abutments differ in that interface I results in an "in line" arrangement of abutting molecules and the interface II in a "zigzag" arrangement. So far as can be determined (the electron density could only be traced on one side of the cross-links), it is the gamma-chains of the newly observed zigzag units (interface II) that are joined by the reciprocal epsilon-amino-gamma-glutamyl cross-links. Auspiciously, the same novel D-D interface was observed in two lower-resolution crystal structures of human double-D preparations that had been crystallized under unusual circumstances. These observations show that double-D structures are linked in a way that is sufficiently flexible to accommodate different D-D interfaces under different circumstances. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Yang, Z.]] | [[Category: Yang, Z.]] | ||
[[Category: cross-linked fibrin]] | [[Category: cross-linked fibrin]] | ||
[[Category: d:d | [[Category: crystal packing]] | ||
[[Category: d:d interface]] | |||
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