新型β-内酰胺类化合物对金属β-内酰胺酶的抑制研究
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1.抗生素耐药靶酶金属β-内酰胺酶抑制剂的设计合成和生物活性评价(Design,synthesis and bioactivity evaluation of metallo-β-lactamases inhibitors for the target enzyme of antibiotic resistance)
- 关键词：
- 抗生素耐药、金属β-内酰胺酶、β-内酰胺类化合物、酶抑制剂、唑基硫代乙酰胺、antibiotic、resistance、metallo-β-lactamases、β-lactam、compounds、enzyme、inhibitor、azolethioacetamide
- 张亦琳；延永；王学军；梁旭华；
- 《商洛学院；》
- 2020年
- 报告
金属β-内酰胺酶(MβLs)介导的抗生素耐药严重威胁世界公共卫生安全。MβLs能够水解几乎所有β-内酰胺类抗生素，而MβLs活性位点结构的多样性限制了广谱MβLs抑制剂的发展。我们设计并合成一系列新型氮杂环硫代乙酰胺类中间体和β-内酰胺类抑制剂，采用酶动力学、MIC、ITC方法评价其抑制MβLs及其耐药菌的活性，运用分子对接和共结晶技术研究抑制剂-MβLs的相互作用，探索MβLs抑制剂的结构活性关系。合成的37个氮杂环硫代乙酰胺类中间体对三个亚组MβLs展现了不同程度的抑制活性,Ki和IC50值均在38.9-0.074 μM,均为混合型抑制剂，其中8个化合物能够使头孢唑林钠抑制E.coli-ImiS的能力提高2-4倍。作用机制研究显示这类化合物通过与活性位点重要的氨基酸残基(如Asp120和Asn233等)结合，改变活性位点的结构，实现对MβLs的抑制。分子中酚羟基、唑基和酰胺基团通过结合MβLs活性中心金属锌离子及其活性位点氨基酸，对氮杂环硫代乙酰胺类化合物的抑制活性有重要作用，最低结合能处于-6.23至-12.64 kcal/mol。美罗培南母核结构MAP对MβLs具有广谱抑制活性,IC50值最低为2.8 μM;MAP能够协同临床抗生素有效提高耐药菌的药物敏感性，使抗生素的MIC值降低4-16倍，其中对诺氟沙星的增效作用最为明显;MAP结构中硝基是优势基团，可通过与周边残基形成氢键从而提高化合物活性。基于β-内酰胺类抗生素分子的母核结构，合成了一种新型头孢菌素类的化合物ASC,并对其合成工艺进行了探究。ASC是一个广谱、竞争型的MβLs抑制剂,MβLs水解ASC的速度要比水解头孢唑啉和亚胺培南快2-6倍，同时ASC是一个良好的抗S.aureus试剂，其使头孢曲松钠的抗菌活性提高了1000倍之多。这些研究成果为进一步探寻广谱MβLs抑制剂可能的结构特征，为临床可用MβLs抑制剂的突破提供重要信息。Antibiotic resistance mediated by metallo-β-lactamases(MβLs)seriously threatens the safety of public health in the world.MβLs can hydrolyze almost all β-lactam antibiotics,but the development of broad-spectrum MβLs inhibitors is challenging due to structural diversity of the active site by these enzymes.In this project,a series of novel azole thioacetamide intermediates and β-lactam inhibitors were designed and synthesized.Enzyme kinetics,MIC and ITC methods were used to evaluate the inhibitory activity for MβLs and its resistant bacteria.Molecular docking and co-crystallization techniques were used to study the interaction of MβLs-inhibitors and explore the structural activity relationship of MβLs inhibitors.The 37 synthetic thioacetamide intermediates showed different mixed inhibitory activities on three subgroups of MβLs with Ki and IC50 values ranged from 38.9 to 0.074 μM.Among them,8 compounds can increase the pesticide effect of cefazolin sodium to inhibit E.coli-ImiS by 2-4 times.The mechanism study showed that these compounds achieve the inhibition of MβLs by binding to the important amino acid residues at the active site(such as Asp120 and Asn233)to change the structure of the active site.The phenolic hydroxyl group,azole group and amide group in the molecule play an important role in in binding to the active center metal zinc ion and surrounding amino acid,with the lowest binding energy ranging from-6.23 to-12.64 kcal/mol.MAP(meropet's mother nucleus)is a broad-spectrum and competitive MβLs inhibitor with the lowest IC50 value of 2.8 μM;MAP can effectively improve drug sensitivity of resistant bacteria in collaboration with clinical antibiotics,and the MIC value reduces by 4-16 times.The nitro group is the dominant group to improve the inhibitory activity by forming hydrogen bonds with surrounding residues of MβLs.Based on the structure of β-lactam antibiotics,a new cephalosporin compound ASC was obtained,and the synthetic technology was explored.ASC can be seemed as a rare potential broad and competive MβLs inhibitor.It shows that MβLs can hydrolysize ASC more quickly(2-6 times).In addition,ASC as inhibitor acted with clinical antibiotics can greatly reduce the usage of Ceftriaxone sodium and the largest reduction can reach 1000 times against staphylococcus aureus.Overall the results enable the seeking of possible structural characteristics of broad spectrum MβLs inhibitors and provides important information.
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