Solution conformation of a peptide fragment representing a proposed RNA-binding site of a viral coat protein studied by two-dimensional NMR

Journal Article · Tue Jun 11 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00237a013· OSTI ID:5077633

van der Graaf, M; van Mierlo, C P.M.; Hemminga, M A ^[1]

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1. Agricultural Univ., Dreijenlaan (Netherlands)

The first 25 amino acids of the coat protein of cowpea chlorotic mottle virus are essential for binding the encapsidated RNA. Although an {alpha}-helical conformation has been predicted for this highly positively charged N-terminal region. No experimental evidence for this conformation has been presented so far. In this study, two-dimensional proton NMR experiments were performed on a chemically synthesized pentacosapeptide containing the first 25 amino acids of this coat protein. All resonances could be assigned by a combined use of two-dimensional correlated spectroscopy and nuclear Overhauser enhancement spectroscopy carried out at four different temperatures. Various NMR parameters indicate the presence of a conformational ensemble consisting of helical structures rapidly converting into more extended states. Differences in chemical shifts and nuclear Overhauser effects indicate that lowering the temperature induces a shift of the dynamic equilibrium toward more helical structures. At 10{degrees}C, a perceptible fraction of the conformational ensemble consists of structures with an {alpha}-helical conformation between residues 9 and 17, likely starting with a turnlike structure around Thr9 and Arg10. Both the conformation and the position of this helical region agree well with the secondary structure predictions mentioned above.

• OSTI ID: 5077633
• Journal Information: Biochemistry; (United States), Vol. 30:23; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
PROTEINS
AMINO ACID SEQUENCE
VIRUSES
NUCLEAR MAGNETIC RESONANCE
CHEMICAL SHIFT
OVERHAUSER EFFECT
PROTONS
RNA
TEMPERATURE DEPENDENCE
BARYONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MAGNETIC RESONANCE
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEIC ACIDS
NUCLEONS
ORGANIC COMPOUNDS
PARASITES
RESONANCE
550601* - Medicine- Unsealed Radionuclides in Diagnostics