Secondary structure of complement component C3a anaphylatoxin in solution as determined by NMR spectroscopy: Differences between crystal and solution conformations

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.85.14.5036· OSTI ID:5516358

Nettesheim, D G; Edalji, R P; Mollison, K W; Greer, J; Zuiderweg, E R.P. ^[1]

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1. Abbott Labs., Abbot Park, IL (USA)

Two-dimensional {sup 1}H NMR investigations were used to locate elements of regular secondary structure in the human complement protein C3a (the des-Arg{sup 77} derivative) in solution. The results were compared to a refined crystal structure based on the 3.2-{angstrom} resolution structure of des-Arg{sup 77}-C3a. In excellent agreement with the x-ray data, helices occur in the regions of residues 17-28 and 36-43 in solution. In contrast to the x-ray data, where a third long helix was found from residue 47 to residue 73, the solution data show a shorter helix in the region from residue 47 to residue 66, followed by a transition range at positions 67-70, leading into a six-residue carboxyl-terminal peptide in dynamic random coil conformation. At the amino terminus, a well-defined helix is observed in solution for the residues 8-15 region, which, like the carboxyl terminus, gradually changes to dynamic random coil toward the end of the polypeptide chain. This is at variance with the x-ray data as well, in which residues 13-15 are nonhelical and no electron density could be assigned to the first 12 residues due to disorder.

• OSTI ID: 5516358
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 85:14; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANTIGENS
AQUEOUS SOLUTIONS
BARYONS
BLOOD SERUM
COHERENT SCATTERING
COMPLEMENT
CRYSTALLOGRAPHY
DIFFRACTION
DISPERSIONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC RESONANCE
MATERIALS
MIXTURES
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC COMPOUNDS
OVERHAUSER EFFECT
PROTEINS
PROTONS
RESONANCE
SCATTERING
SOLUTIONS
TOXIC MATERIALS
TOXINS
X-RAY DIFFRACTION