Callipeltin A, an Anti-HIV Cyclic Depsipeptide from the New Caledonian Lithistida Sponge <i>Callipelta </i>sp<i>.</i>

Abstract

Callipeltin A (1) 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 (1), which possesses the N-terminus blocked with a β-hydroxy acid, and the C-terminus lactonized with a threonine residue, was determined by interpretation 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 residues: β-methoxytyrosine (βOMeTyr), (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.