Proton nuclear magnetic resonance characterization of the aromatic residues in the variant-3 neurotoxin from Centruroides sculpturatus Ewing

Journal Article · Tue Feb 21 00:00:00 EST 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00430a020· OSTI ID:5648853

Krishna, N R; Nettesheim, D G; Klevit, R E; Drobny, G; Watt, D D; Bugg, C E ^[1]

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1. Univ. of Alabama, Birmingham (USA)

The amino acid sequence for the variant-3 (CsE-v3) toxin from the venom of the scorpion Centruroides sculpturatus Ewing contains eight aromatic residues. By use of 2D NMR spectroscopic methods, the resonances from the individual protons (NH, C{sup alpha}H, C{sup beta}H{prime}, H{double prime}, and the ring) for each of the individual aromatic residues have been completely assigned. The spatial arrangement of the aromatic ring systems with respect to each other has been qualitatively analyzed by 2D-NOESY techniques. The results show that Trp-47, Tyr-4, and Tyr-42 are in close spatial proximity to each other. The NOESY contacts and the ring current induced shifts in the resonances of the individual protons of Tyr-4 and Trp-47 suggest that the aromatic ring planes of these residues are in an orthogonal arrangement. A comparison with the published crystal structure suggests that there is a minor rearrangement of the aromatic rings in the solution phase. No 2D-NOESY contacts involving Phe-44 and Tyr-14 to any other aromatic ring protons have been observed. The pH dependence of the aromatic ring proton chemical shifts has also been studied. These results suggest that the Tyr-58 phenolic group is experiencing a hydrogen-bonding interaction with a positively charged group, while Tyr-4, -14, -38, and -40 are experiencing through-space interactions with proximal negatively charged groups. These studies define the microenvironment of the aromatic residues in the variant-3 neurotoxin in aqueous solution.

• OSTI ID: 5648853
• Journal Information: Biochemistry; (USA), Vol. 28:4; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
TOXINS
NUCLEAR MAGNETIC RESONANCE
AMINO ACID SEQUENCE
HEAVY WATER
NMR SPECTRA
OVERHAUSER EFFECT
PH VALUE
PROTONS
SCORPIONS
TRYPTOPHAN
AMINO ACIDS
ANIMALS
ANTIGENS
ARACHNIDS
AROMATICS
ARTHROPODS
AZAARENES
AZOLES
BARYONS
CARBOXYLIC ACIDS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INDOLES
INVERTEBRATES
MAGNETIC RESONANCE
MATERIALS
MOLECULAR STRUCTURE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PYRROLES
RESONANCE
SPECTRA
TOXIC MATERIALS
WATER
550601* - Medicine- Unsealed Radionuclides in Diagnostics