dc:description"Fig. 1. Structural representation of (A) trihydroxy-decahydro-37-methyl-macrobrevin (compound 1), (B) hexahydro-macrobrevin (compound 2), (C) hexahydro-41- hydroxy-macrobrevin-31-acetate (compound 3), and (D) hexahydro-28-nor-methyl-5-methoxy-macrobrevin (compound 4) isolated from marine macroalgaassociated B. amyloliquefaciens MTCC 12713. (E) The zone of inhibition (34 mm) observed with hexahydro-41-hydroxy-macrobrevin-31-acetate (compound 3) against VREfs as visualized on Mueller Hinton agar plates by disc diffusion assay was illustrated. The amounts of compound 3 and chloramphenicol were 30 μg per disc. Chloramphenicol and ethyl acetate, which were used as the positive and negative control, were denoted with (+) and (), respectively.";
dc:description"Fig. 4. Proposed biosynthesis of 21- membered macrocyclic lactones classified as macrobrevin analogues (1–4) in B. amyloliquefaciens through successive decarboxylative Claisen condensation between acetyl-S-KS domain and malonate-S- ACP units. Claisen condensation was activated by acyl carrier protein (ACP), ketoreductase (KR), ketosynthase (KS), thioesterase (TE), dehydratase (DH), methyl transferase (MT), acyl transferase (AT), enoyl reductase (ER) and S-adenosyl-methionine (SAM). The elongation process comprised of 16 modules with KS, KR and ACP domains. The initial step includes the decarboxylative Claisen condensation between 2-methylbutanethioic-S-KS and malonate-S-ACP. The final step of macrobrevin formation could occur through the cyclization of linear chain of 21-membered carbon framework by TE. Consequently, alterations of 21-membered carbon framework classified as macrobrevin scaffold could result in the formation of macrobrevin analogues 1–4.";
dc:description"Fig. 5. (A) Molecular docking interfaces of 41-hydroxy-macrobrevin-31-acetate (compound 3) with S. aureus peptide deformylase (SaPDF). 3D docking analysis of the titled macrobrevin analogue (ligand) and S. aureus PDF crystal structure (PDB ID: 1LQW) were conformationally structured (Swiss-Pdb Viewer, SPDBV, version 4.1.0). The primary algorithm used by AutoDock for conformational searching was the Lamarckian Genetic Algorithm (LGA) showing four hydrogen bonds each (displayed as red and bluecoloured lines) in the binding site, whereas USCF Chimera (University of California, San Francisco, ver. 1.11.2) software reinforced the visualizations of the best molecular docking positions of the compound and target protein. The contact residues were shown and labeled by type and number in the background. Compound 3 exhibited least binding energy among the titled compounds. (B) Illustrative representation of 41-hydroxy-macrobrevin-31-acetate (compound 3) forming hydrogen bond interactions with the amino acyl residues in the active site of SaPDF. Compound (3) displayed maximum number of hydrogen bond interactions (GLN141 at 3.118 Å, LYS84 at 3.789 Å and 3.388 Å, and ARG143 at 3.483 Å). (C) Drug-likeness score obtained for the compound (3) with molsoft software. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)";
