Wall Teichoic Acid Biosynthesis: A New Target for Therapeutic Intervention?

描述(申请人提供)：抗生素耐药性对公众健康构成重大威胁。近年来出现的几种对万古霉素耐药的金黄色葡萄球菌菌株尤其令人恐惧，因为金黄色葡萄球菌是一种高度毒力的病原体。迫切需要新的策略来治疗耐药的革兰氏阳性感染。这项拟议研究的长期目标是评估一种基本上未被探索的代谢途径作为抗菌化疗的靶点。在许多致病性革兰氏阳性细菌中发现的这一途径，涉及壁磷壁酸(WTAS)的生物合成。壁磷壁酸是表面缔合的阴离子聚合物。在一些生物体中，这些聚合物对生存是必不可少的；在金黄色葡萄球菌中，它们作为毒力因子发挥作用，在感染的建立和传播中发挥关键作用。因此，干扰壁磷壁酸生物合成的策略可能具有治疗作用。本研究的具体目的包括：1)阐明主要革兰氏阳性模式生物枯草杆菌WTA生物合成关键酶的酶学性质。将开发化学方法、途径和工具来研究枯草杆菌168中参与WTA生物合成的三种酶TagA、TAGB和TagF。我们将探索这些酶的不同寻常的特征。Ii)结合遗传学和体外生物化学研究金黄色葡萄球菌WTA生物合成途径。为研究6.枯草杆菌酶而开发的方法将被用于表征金黄色葡萄球菌的酶。关于金黄色葡萄球菌中WTA生物合成的悬而未决的问题将被解决。3)建立壁磷壁酸生物合成的多靶点高通量筛选体系。将建立和实施涉及WTA生物合成的几种连续酶的体外筛选，并将针对枯草杆菌和金黄色葡萄球菌目标进行评估。该提案中概述的实验将为评估壁磷壁酸的生物合成作为抗菌化疗的靶点奠定基础，并将提供关于金黄色葡萄球菌WTA途径和一些更有趣的WTA酶的基本信息。

DESCRIPTION (provided by applicant): Antibiotic resistance poses a significant threat to public health. The emergence of several vancomycin-resistant Staphylococcus aureus strains in recent years is particularly frightening because S. aureus is a highly virulent pathogen. There is a pressing need for new strategies to treat resistant Gram positive infections. The long term goal of the proposed research is to evaluate a largely unexplored metabolic pathway as a target for antimicrobial chemotherapy. This pathway, found in many pathogenic Gram positive bacteria, involves the biosynthesis of wall teichoic acids (WTAs). Wall teichoic acids are surface-associated anionic polymers. In some organisms these polymers are essential for survival; in S. aureus, they function as virulence factors that play a critical role in the establishment and spread of infection. Therefore, strategies to disrupt wall teichoic acid biosynthesis may have therapeutic utility. The specific aims of the research include: I) Elucidating the enzymology of key WTA biosynthetic enzymes from B. subtilis, the major Gram positive model organism. Chemical methods, approaches, and tools will be developed to study TagA, TagB, and TagF, three enzymes involved in WTA biosynthesis in B. subtilis 168. Unusual features of these enzymes will be explored. II) Characterizing the pathway for WTA biosynthesis in S. aureus using a combination of genetics and in vitro biochemistry. The approaches developed to study the 6. subtilis enzymes will be applied to characterize the S. aureus enzymes. Unresolved questions about WTA biosynthesis in S. aureus will be addressed. III) Establishing a multi-target high throughput screen for wall teichoic acid biosynthesis. An in vitro screen for several successive enzymes involved in WTA biosynthesis will be established and implemented, and the hits will be evaluated against B. subtilis and S. aureus targets. The experiments outlined in this proposal will lay the groundwork for evaluating wall teichoic acid biosynthesis as a target for antimicrobial chemotherapy and will provide fundamental information about the WTA pathway in S. aureus and about some of the more interesting WTA enzymes.