Design of multi-target D-Ala-D-Ala ligase ligands

描述(申请人提供)：结核分枝杆菌是当今的一种主要流行病，每年在世界范围内造成800万新病例和300万人死亡。迫切需要通过新机制发挥作用的新的抗结核药物，以便与现有药物相结合进行更有效的治疗，并治疗近年来出现的多重耐药菌株。细菌细胞壁含有能抵抗外界渗透压力的肽聚糖。肽聚糖生物合成的靶向步骤是新抗菌药物的一个有吸引力的机制。合成D-丙氨酰-D-丙氨酸二肽(D-Ala-D-Ala)是合成肽聚糖和交联肽多糖所必需的一个基本步骤。催化这一过程的酶是D-丙氨酰-D-丙氨酸连接酶(DDL)。由于D-丙氨酸-D-丙氨酸的合成是细菌生长所必需的过程，因此DDL是开发新型抗生素的极佳靶标，而且目前还没有与DDL类似的药物。我们应用了一种基于电子结构的方法来鉴定和分析DDL ATP和底物位点结合配体，使用在HTS筛选中显示出抗结核分枝杆菌H37Rv活性的化合物集，以及显示出与DDL结构相似的激酶结合配体。我们建议在拟议的工作的前半部分改进和验证DDL结合预测协议，并利用这些协议来鉴定和检测基于有效抗结核靶标的已知支架的化合物对DDL的活性。 公共卫生相关性：迫切需要通过新机制发挥作用的新的抗结核药物，以更有效地治疗结核病和治疗最近出现的多重耐药菌株。在这项建议中，我们应用了一种基于电子结构的方法来鉴定和分析新的有效的DDL结合剂和多TB靶标配体。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is a major epidemic today, causing 8 million new cases and 3 million deaths yearly world-wide. New anti-tubercular drugs that act through novel mechanisms are urgently needed for more efficacious treatments in combination with existing drugs and for treating multi-drug resistant strains that emerged in recent years. The bacterial cell wall contains peptidoglycan that provides resistance from external osmotic pressure. Targeting steps of peptidoglycan biosynthesis is an attractive mechanism for new antibacterial agents. An essential step is the synthesis of D-Alanyl-D-Alanine dipeptide (D-Ala-D-Ala) that is required for the formation of peptidoglycan and for cross-linking peptidoglycan strands. The enzyme catalyzing this process is D-Alanyl-D-Alanine ligase (DDl). DDl is an excellent target for new antibiotics since synthesis of D-Ala-D-Ala is an essential process for bacterial growth and furthermore there is no human equivalent to DDl. We have applied an in silico structure based approach to identify and assay DDl ATP and substrate site binding ligands using sets of compounds that have shown activity against M. tuberculosis TB H37Rv in HTS screening and kinase binding ligands that show structural similarities to DDl. We propose to refine and validate DDl binding prediction protocols in the first half of the proposed effort and utilize these to identify and assay compounds based on known scaffolds of valid anti-tubercular targets for activity against DDl. PUBLIC HEALTH RELEVANCE: New anti-tubercular drugs that act through novel mechanisms are urgently needed for more efficacious treatments of tuberculosis and for treating multi-drug resistant strains that recently emerged. In this proposal we have apply an in silico structure based approach to identify and assay novel potent DDl binders and multi- TB target ligands.