Callipeltin A, an anti-HIV cyclic depsipeptide from the New Caledonian Lithistida sponge Callipelta sp.

Callipeltin A is a cyclic depsidecapeptide from a shallow water sponge of the genus Callipelta (order Lithistida), collected in the waters off New Caledonia. The structure of callipeltin A, which possesses the N-terminus blocked with a b-hydroxy acid, and the C-terminus lactonized with a threonine residue, was detd. by interpretation of spectral data, chem. degrdn., and evaluation of the amino acids obtained by acid hydrolysis. Along with four common L-, one D-, and two N-Me amino acids, it contains three new amino acid residues: b-methoxytyrosine (bOMeTyr), (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid (AGDHE), and (3S,4R)-3,4-dimethyl-L-glutamine. Callipeltin A (1) has been found to protect cells infected by human immunodeficiency (HIV) virus.