2IC4

Solution structure of the His402 allotype of the Factor H SCR6-SCR7-SCR8 fragment

DOI: 10.2210/pdb2IC4/pdb

Classification: IMMUNE SYSTEM
Organism(s): Homo sapiens
Expression System: Escherichia coli BL21
Mutation(s): Yes

Deposited: 2006-09-12 Released: 2007-04-10
Deposition Author(s): Fernando, A.N., Furtado, P.B., Gilbert, H.E., Clark, S.J., Day, A.J., Sim, R.B., Perkins, S.J.

Experimental Data Snapshot

Method: SOLUTION SCATTERING

wwPDB Validation 3D Report Full Report

This is version 1.3 of the entry. See complete history.

Literature

Associative and Structural Properties of the Region of Complement Factor H Encompassing the Tyr402His Disease-related Polymorphism and its Interactions with Heparin.

Fernando, A.N., Furtado, P.B., Clark, S.J., Gilbert, H.E., Day, A.J., Sim, R.B., Perkins, S.J.

(2007) J Mol Biol 368: 564-581

PubMed: 17362990 Search on PubMed
DOI: 10.1016/j.jmb.2007.02.038
Primary Citation of Related Structures:
2IC4

PubMed Abstract:

Factor H (FH) is a major complement control protein in serum. The seventh short complement regulator (SCR-7) domain of the 20 in FH is associated with age-related macular degeneration through a Tyr402His polymorphism. The recombinant SCR-6/8 domains containing either His402 or Tyr402 and their complexes with a heparin decasaccharide were studied by analytical ultracentrifugation and X-ray scattering. The sedimentation coefficient is concentration dependent, giving a value of 2.0 S at zero concentration and a frictional ratio f/f(o) of 1.2 for both allotypes. The His402 allotype showed a slightly greater self-association than the Tyr402 allotype, and small amounts of dimeric SCR-6/8 were found for both allotypes in 50 mM, 137 mM and 250 mM NaCl buffers. Sedimentation equilibrium data were interpreted in terms of a monomer-dimer equilibrium with a dissociation constant of 40 microM for the His402 form. The Guinier radius of gyration R(G) of 3.1-3.3 nm and the R(G)/R(O) ratio of 2.0-2.1 showed that SCR-6/8 is relatively extended in solution. The distance distribution function P(r) showed a maximum dimension of 10 nm, which is less than the length expected for a linear domain arrangement. The constrained scattering and sedimentation modelling of FH SCR-6/8 showed that bent SCR arrangements fit the data better than linear arrangements. Previously identified heparin-binding residues were exposed on the outside curvature of this bent domain structure. Heparin caused the formation of a more linear structure, possibly by binding to residues in the linker. It was concluded that the His402 allotype may self-associate more readily than the Tyr402 allotype, SCR-6/8 is partly responsible for the folded-back structure of intact FH, and SCR-6/8 changes conformation upon heparin binding.

Related Citations:

Folded-back Solution Structure of Monomeric Factor H of Human Complement by Synchrotron X-ray and Neutron Scattering, Analytical Ultracentrifugation and Constrained Molecular Modelling
Aslam, M., Perkins, S.J.
(2001) J Mol Biol 309: 1117

Organizational Affiliation:

Department of Biochemistry and Molecular Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK.

Macromolecules

Find similar proteins by:

(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Complement factor H	A	187	Homo sapiens	Mutation(s): 1 Gene Names: CFH, HF, HF1, HF2
UniProt & NIH Common Fund Data Resources
Find proteins for P08603 (Homo sapiens) Explore P08603 Go to UniProtKB: P08603
PHAROS: P08603 GTEx: ENSG00000000971
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Reference Sequence