The marine bacterium Roseovarius tolerans EL-164 (Rhodobacteraceae) can produce unique N-acylalanine methyl esters (NAMEs) besides strucutrally related N-acylhomoserine lactones (AHLs), bacterial signaling compounds widespread in the Rhodobacteraceae. The structures of two unprecedented NAMEs carrying a rare terminally oxidized acyl chain are reported here. The compounds (Z)-N-16-hydroxyhexadec-9-enoyl-l-alanine methyl ester (Z9-16-OH-C16:1-NAME, 3) and (Z)-N-15-carboxypentadec-9-enoyl-l-alanine methyl ester (16COOH-C16:1-NAME, 4) were isolated, and the structures were determined by NMR and MS experiments. Both compounds were synthesized to prove assignments and to test their biological activity. Finally, non-natural, structurally related Z9-3-OH-C16:1-NAME (18) was synthesized to investigate the mass spectroscopy of structurally related NAMEs. Compound 3 showed moderate antibacterial activity against microorganisms such as Bacillus, Streptococcus, Micrococcus, or Mucor strains. In contrast to AHLs, quorum-sensing or quorum-quenching activity was not observed.

中文翻译：

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海洋细菌Roseovarius tolerans EL-164的含氧N-酰基丙氨酸甲基酯（NAME）

除结缔组织相关的N-酰基高丝氨酸内酯（AHLs）（在红细菌科中广泛存在的细菌信号化合物）外，海洋细菌耐受性玫瑰红细菌EL-164（红杆菌科）还可以产生独特的N-酰基丙氨酸甲酯（NAMEs）。这里报道了两个罕见的带有稀有的末端氧化酰基链的NAMEs的结构。化合物（Z）-N -16-羟基十六烷基-9-烯酰基-1-丙氨酸甲酯（Z9-16-OH-C16：1-NAME，3）和（Z）-N -15-羧基戊烯-9-烯酰基-升-丙氨酸甲酯（16COOH-C16：1-NAME，4分离），并通过NMR和MS实验确定结构。合成了这两种化合物以证明其归属并测试其生物学活性。最后，合成了非天然的，结构上相关的Z9-3-OH-C16：1-NAME（18），以研究结构上相关的NAME的质谱。化合物3对诸如芽孢杆菌，链球菌，微球菌或Mucor菌株等微生物表现出中等的抗菌活性。与AHL相比，未观察到群体感应或群体猝灭活动。