CALLIPELTIN-A, AN ANTI-HIV CYCLIC DEPSIPEPTIDE FROM THE NEW CALEDONIAN LITHISTIDA SPONGE CALLIPELTA SP

Callipeltin A (1) is a cyclic depsidecapeptide from a shallow water sp onge of the genus Callipelta (order Lithistida), collected in the wate rs off New Caledonia. The structure of callipeltin A (1), which posses ses the N-terminus blocked with a beta-hydroxy acid, and the C-terminu s lactonized with a threonine residue, was determined by interpretatio n of spectral data, chemical degradation, and evaluation of the amino acids obtained by acid hydrolysis. Along with four common L-, one D-, and two N-methyl amino acids, it contains three new amino acid residue s: beta-methoxytyrosine (beta OMeTyr), ,3R,4S)-4-amino-7-guanidino-2,3 -dihydroxyheptanoic acid (AGDHE), and (3S,4R)- 3,4-dimethyl-L-glutamin e. Callipeltin A (1) has been found to protect cells infected by human immunodeficiency (HIV) virus.