The solution conformation of the antibacterial peptide cecropin A: A nuclear magnetic resonance and dynamical simulated annealing study

Journal Article · Tue Oct 04 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00420a008· OSTI ID:7009063

Holak, T A; Gronenborn, A M; Clore, G M ^[1]; Engstroem, A; Kraulis, P J; Lindeberg, G; Bennich, H; Jones, T A ^[2]

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1. Max-Planck-Institut fuer Biochemic, Munchen (West Germany)
2. Unif. of Uppsala (Sweden)

The solution conformation of the antibacterial polypeptide cecropin A from the Cecropia moth is investigated by nuclear magnetic resonance (NMR) spectroscopy under conditions where it adopts a fully ordered structure, as judged by previous circular dichroism studies. By use of a combination of two-dimensional NMR techniques the {sup 1}H NMR spectrum of cecropin A is completely assigned. A set of 243 approximate interproton distance restraints is derived from nuclear Overhauser enhancement (NOE) measurements. These, together with 32 restraints for the 16 intrahelical hydrogen bonds identified on the basis of the pattern of short-range NOEs, form the basis of a three-dimensional structure determination by dynamical simulated annealing. The calculations are carried out starting from three initial structures, an {alpha}-helix, an extended {beta}-strand, and a mixed {alpha}/{beta} structure. Seven independent structures are computed from each starting structure by using a different random number seeds for the assignments of the initial velocities. Analysis of the 21 converged structure indicates that there are two helical regions extending from residues 5 to 21 and from residues 24 to 37 which are very well defined in terms of both atomic root mean square differences and backbone torsion angles. The long axes of the two helices lie in two planes, which are at an angle of 70-100{degree} to each other. The orientation of the helices within these planes, however, cannot be determined due to the paucity of NOEs between the two helices.

• OSTI ID: 7009063
• Journal Information: Biochemistry; (USA), Vol. 27:20; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ANTIMICROBIAL AGENTS
NUCLEAR MAGNETIC RESONANCE
ANNEALING
GEOMETRY
MOLECULAR STRUCTURE
OVERHAUSER EFFECT
PEPTIDES
PROTONS
ANTI-INFECTIVE AGENTS
BARYONS
DRUGS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HEAT TREATMENTS
MAGNETIC RESONANCE
MATHEMATICS
NUCLEONS
ORGANIC COMPOUNDS
PROTEINS
RESONANCE
550601* - Medicine- Unsealed Radionuclides in Diagnostics