Sequence determination and resonance assignments of an Azomonas siderophore using C-13 natural abundance C-13-H-1 HNCA experiment

The determination of the amino acid sequence of small peptides as sideropho res is commonly performed using long-range HMBC correlation experiments. Ho wever, this type of experiment can lead to ambiguities in the assignment re sulting in erroneous primary sequence determination. In this paper, we prop ose to use an HNCA type experiment on a N-15-labelled sample in order to av oid these ambiguities. This experiment was successfully used to determine t he primary sequence of azoverdin, a siderophore produced by Azomonas. (C) 2 001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.