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1 H and 15 N nuclear magnetic resonance assignment and secondary structure of the cytotoxic ribonuclease α‐Sarcin
Author(s) -
CamposOlivas Ramon,
Bruix Marta,
Santoro Jorge,
Rico Manuel,
Pozo Alvaro Martinez Del,
Lacadena Javier,
Gavilanes José G.
Publication year - 1996
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560050519
Subject(s) - heteronuclear molecule , homonuclear molecule , ribonuclease , protein secondary structure , chemistry , stereochemistry , nuclear magnetic resonance spectroscopy , peptide bond , crystallography , rna , amino acid , biochemistry , molecule , organic chemistry , gene
The ribosome‐inactivating protein α‐Sarcin (αS) is a 150‐residue fungal ribonuclease that, after entering sensitive cells, selectively cleaves a single phosphodiester bond in an universally conserved sequence of the major rRNA to inactivate the ribosome and thus exert its cytotoxic action. As a first step toward establishing the structure‐dynamics‐function relationships in this system, we have carried out the assignment of the 1 H and 15 N NMR spectrum of αS on the basis of homonuclear ( 1 H‐ 1 H) and heteronuclear ( 1 H‐ 15 N) two‐dimensional correlation spectra of a uniformly 15 N‐labeled sample, and two selectively 15 N‐labeled (Tyr and Phe) samples, as well as a single three‐dimensional experiment. The secondary structure of αS, as derived from the characteristic patterns of dipolar connectivities between backbone protons, conformational chemical shifts, and the protection of backbone amide protons against exchange, consists of a long N‐terminal β‐hairpin, a short α‐helical segment, and a C‐terminal β‐sheet of five short strands arranged in a+1,+1,+ 1, + 1 topology, connected by long loops in which the 13 Pro residues are located.