Methionine aminopeptidases (MetAPs) have been recognized as drug targets and have been extensively studied for discovery of selective inhibitors. MetAPs are essential enzymes in all living cells. While most prokaryotes contain a single gene, some prokaryotes and all eukaryotes including human have redundancy. Due to the similarity in the active sites of the MetAP enzyme between the pathogens and human limited the success of discovering selective inhibitors. We recently have discovered that MetAPs with small inserts within the catalytic domain to have different susceptibilities against some inhibitors compared to those that do not have. Using this clue we used bioinformatic tools to identify new variants of MetAPs with inserts in pathogenic species. Two new isoforms were identified in Vibrio species with two and three inserts in addition to an isoform without any insert. Multiple sequence alignment suggested that inserts are conserved in several of the Vibrio species. Two of the three inserts are common between two and three insert isoforms. One of the inserts is identified to have “NNKNN” motif that is similar to well-characterized quorum sensing peptide, “NNWNN”. Another insert is predicted to have a posttranslational modification site. Three Vibrio proteins were cloned, expressed, purified, enzyme kinetics established and inhibitor screening has been performed. Several of the pyridinylpyrimidine derivatives selectively inhibited MetAPs with inserts compared to those that do not have, including the human enzyme. Crystal structure and molecular modeling studies provide the molecular basis for selective inhibition.

蛋氨酸氨基肽酶（MetAPs）已被公认为是药物靶标，并已被广泛研究以发现选择性抑制剂。MetAP是所有活细胞中必不可少的酶。尽管大多数原核生物都包含单个基因，但某些原核生物和包括人在内的所有真核生物都具有冗余性。由于病原体和人类之间MetAP酶的活性位点相似，因此发现选择性抑制剂的成功受到限制。我们最近发现，与没有抑制剂的MetAP相比，在催化域内插入小分子的MetAP对某些抑制剂的敏感性不同。利用这一线索，我们使用了生物信息学工具来鉴定具有致病性物种插入片段的MetAP的新变体。在V ibrio中鉴定出两个新的亚型种具有两个和三个插入物，以及没有任何插入物的同工型。多个序列比对表明插入物在几个弧菌属物种中是保守的。三个插入物中的两个在两个和三个插入同工型之间是相同的。插入物之一被鉴定为具有“ NNKNN”基序，其与特征明确的群体感应肽“ NNWNN”相似。预计另一个插入片段具有翻译后修饰位点。三V ibrio克隆，表达，纯化蛋白质，建立酶动力学，并进行了抑制剂筛选。与没有插入片段的包括人酶相比，一些吡啶基嘧啶衍生物选择性地抑制了带有插入片段的MetAP。晶体结构和分子模型研究为选择性抑制提供了分子基础。