PDBsum entry 2jor

Blood clotting

PDB id: 2jor

Contents

Protein chain

79 a.a. *

* Residue conservation analysis

PDB id:

2jor

Name:

Blood clotting

Title:

Nmr solution structure, stability, and interaction of the recombinant bovine fibrinogen alphac-domain fragment

Structure:

Fibrinogen alpha chain. Chain: a. Fragment: alpha-c domain. Engineered: yes

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Gene: fga. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

20 models

Authors:

R.A.Burton,G.Tsurupa,H.Roy,T.Nico,M.Leonid

Key ref:

R.A.Burton et al. (2007). NMR solution structure, stability, and interaction of the recombinant bovine fibrinogen alphaC-domain fragment. Biochemistry, 46, 8550-8560. PubMed id: 17590019

Date:

20-Mar-07 Release date: 07-Aug-07

Protein chain

P02672  (FIBA_BOVIN) -  Fibrinogen alpha chain from Bos taurus

Seq: 615 a.a.

Struc: 79 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Biochemistry 46:8550-8560 (2007)

PubMed id: 17590019

NMR solution structure, stability, and interaction of the recombinant bovine fibrinogen alphaC-domain fragment.

R.A.Burton, G.Tsurupa, R.R.Hantgan, N.Tjandra, L.Medved.

ABSTRACT

According to the existing hypothesis, in fibrinogen, the COOH-terminal portions of two Aalpha chains are folded into compact alphaC-domains that interact intramolecularly with each other and with the central region of the molecule; in fibrin, the alphaC-domains switch to an intermolecular interaction resulting in alphaC-polymers. In agreement, our recent NMR study identified within the bovine fibrinogen Aalpha374-538 alphaC-domain fragment an ordered compact structure including a beta-hairpin restricted at the base by a 423-453 disulfide linkage. To establish the complete structure of the alphaC-domain and to further test the hypothesis, we expressed a shorter alphaC-fragment, Aalpha406-483, and performed detailed analysis of its structure, stability, and interactions. NMR experiments on the Aalpha406-483 fragment identified a second loose beta-hairpin formed by residues 459-476, yielding a structure consisting of an intrinsically unstable mixed parallel/antiparallel beta-sheet. Size-exclusion chromatography and sedimentation velocity experiments revealed that the Aalpha406-483 fragment forms soluble oligomers whose fraction increases with an increase in concentration. This was confirmed by sedimentation equilibrium analysis, which also revealed that the addition of each monomer to an assembling alphaC-oligomer substantially increases its stabilizing free energy. In agreement, unfolding experiments monitored by CD established that oligomerization of Aalpha406-483 results in increased thermal stability. Altogether, these experiments establish the complete NMR solution structure of the Aalpha406-483 alphaC-domain fragment, provide direct evidence for the intra- and intermolecular interactions between the alphaC-domains, and confirm that these interactions are thermodynamically driven.