Gr. Pettit et al., ANTINEOPLASTIC AGENTS .315. ISOLATION AND STRUCTURE OF THE MARINE SPONGE CANCER CELL-GROWTH INHIBITOR PHAKELLISTATIN-5, Bioorganic & medicinal chemistry letters, 4(17), 1994, pp. 2091-2096
The Federated State of Micronesia (Chuuk) marine sponge Phakellia cost
ada has been found to contain (9.6 x 10(-6) % yield) a new human cance
r cell growth inhibitor designated phakellistatin 5 (3). Structural el
ucidation was accomplished employing high resolution FAB tandem MS/MS
and high field (500 MHz) 2D-NMR techniques. Extension of the NMR exper
iments over the temperature range -25 to 25 degrees C allowed the prin
cipal solution conformation of phakellistatin 5 to be assigned (Figure
2). The absolute configuration was found to correspond to S-amino aci
d units except for R-Asn.