View source for 1n73

[[Image:1n73.gif|left|200px]]

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{{STRUCTURE_1n73|  PDB=1n73  |  SCENE=  }} 

'''Fibrin D-Dimer, Lamprey complexed with the PEPTIDE LIGAND: GLY-HIS-ARG-PRO-AMIDE'''


==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.

==About this Structure==
1N73 is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Petromyzon_marinus Petromyzon marinus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N73 OCA]. 

==Reference==
The crystal structure of fragment double-D from cross-linked lamprey fibrin reveals isopeptide linkages across an unexpected D-D interface., Yang Z, Pandi L, Doolittle RF, Biochemistry. 2002 Dec 31;41(52):15610-7. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12501189 12501189]
[[Category: Petromyzon marinus]]
[[Category: Protein complex]]
[[Category: Doolittle, R F.]]
[[Category: Pandi, L.]]
[[Category: Yang, Z.]]
[[Category: Isopeptide cross-linked chain]]
[[Category: Protein-peptide complex]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 02:10:41 2008''