Effect of Pentacyclic Guanidine Alkaloids from the Sponge Monanchora pulchra on Activity of ?-Glycosidases from Marine Bacteria.

ABSTRACT: The effect of monanchomycalin B, monanhocicidin A, and normonanhocidin A isolated from the Northwest Pacific sample of the sponge Monanchora pulchra was investigated on the activity of ?-galactosidase from the marine ?-proteobacterium Pseudoalteromonas sp. KMM 701 (?-PsGal), and ?-N-acetylgalactosaminidase from the marine bacterium Arenibacter latericius KMM 426T (?-NaGa). All compounds are slow-binding irreversible inhibitors of ?-PsGal, but have no effect on ?-NaGa. A competitive inhibitor d-galactose protects ?-PsGal against the inactivation. The inactivation rate (kinact) and equilibrium inhibition (Ki) constants of monanchomycalin B, monanchocidin A, and normonanchocidin A were 0.166 ± 0.029 min-1 and 7.70 ± 0.62 ?M, 0.08 ± 0.003 min-1 and 15.08 ± 1.60 ?M, 0.026 ± 0.000 min-1, and 4.15 ± 0.01 ?M, respectively. The 2D-diagrams of ?-PsGal complexes with the guanidine alkaloids were constructed with "vessel" and "anchor" parts of the compounds. Two alkaloid binding sites on the molecule of ?-PsGal are shown. Carboxyl groups of the catalytic residues Asp451 and Asp516 of the ?-PsGal active site interact with amino groups of "anchor" parts of the guanidine alkaloid molecules.

SUBMITTER: Bakunina I 

PROVIDER: S-EPMC6356649 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature