PROTON NMR-STUDIES OF APO-NEOCARZINOSTATIN FROM STREPTOMYCES-CARZINOSTATICUS - SEQUENCE-SPECIFIC ASSIGNMENT AND SECONDARY STRUCTURE

The sequence‐specific resonance assignment of apo‐neocarzinostatin from Streptomyces carzinostaticus was carried out from two‐dimensional proton‐NMR spectra. The assignments were obtained for the backbone protons of 111 of the 113 residues of the protein, missing the two CαH of one glycine but including 3 of the 4 prolines. The majority of side chain protons were also assigned. The secondary structure derived from the analysis of sequential connections corresponds to ten β‐strands separated by clearly identified loops and turns. Inter‐strand connectivities and slowly exchanging amide protons confirm the presence of the two disulfide bridges from Cys37 to Cys47 and from Cys88 to Cys93 and indicate a global folding similar to that of the similar proteins, actinoxanthin and macromomycin, for which crystallographic data are available. Copyright © 1990, Wiley Blackwell. All rights reserved