Euryjanicin A: a new cycloheptapeptide from the Caribbean marine sponge Prosuberites laughlini

Abstract

A new proline-containing cycloheptapeptide, euryjanicin A (1), has been isolated from the marine sponge Prosuberites laughlini indigenous to Puerto Rico, and its structure established by an X-ray crystal structure determination. The absolute configuration of each amino acid residue was determined by Marfey's method.

Figure 1

¹H (500 MHz) (A) and ¹³C (125 MHz) (B) NMR spectra of euryjanicin A (1) in CDCl₃ at 25 °C. The doubling and tripling of resonances observed in the NMR spectra is attributed to the existence of slow conformational equilibria.

Figure 2

Perspective drawing of the X-ray crystal structure of euryjanicin A (1). Hydrogen atoms have been omitted for clarity and selected atoms are labeled. Carbon atoms are indicated in black, nitrogens in blue, and oxygens in red.