Type II-NDHs in M. tuberculosis respiration and persistence

 描述(申请人提供)：结核分枝杆菌是一种抗酸、人类特有的病原体，是呼吸道疾病结核病(TB)的病原体。目前预计约有20亿人潜伏感染结核杆菌。在潜伏期，结核分枝杆菌在宿主产生的肉芽肿性病变中以一种鲜为人知的生理状态存在，称为非复制持久性(NRP)。一般认为，在肉芽肿性病变中，最初遇到的特殊情况，包括氧气限制和一氧化氮，会抑制有氧呼吸，并诱导结核分枝杆菌在无氧休眠期间转变为NRP，以便长期存活。结核分枝杆菌的需氧和无氧呼吸在一定程度上是由NADH脱氢酶(NDH)介导的，NDH是催化NADH氧化为NAD+的酶，伴随着电子向呼吸链成分的转移。结核分枝杆菌编码一个1型NDH和两个2型NDH。最近，我们确定了第三种预测的2型NDH(Rv1812c)，它受与结核分枝杆菌持久性相关的决定因素/条件调控。本申请中描述的初步研究表明，Rv1812c编码一种2型NDH，并参与将结核分枝杆菌从厌氧休眠中复苏。此外，我们提供的生物信息学证据表明，Rv1812c具有独特的结构、功能和表达特征，这些特征使其有别于结核分枝杆菌产生的另外两种已建立的2型NDH(NDH和NDHA)。本申请中提出的两个特定目标将使我们能够调查和比较结核分枝杆菌产生的三种2型NDH的活性，并确定Rv1812c是否是结核分枝杆菌NRP或其体内潜伏期复苏所必需的。

 DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is an acid-fast, human-specific pathogen and is the etiological agent of the respiratory disease tuberculosis (TB). Approximately 2 billion individuals are currently predicted to be latently infected with the tuberce bacillus. During latency, M. tuberculosis exists within host-generated granulomatous lesions in a poorly understood physiological state termed non-replicating persistence (NRP). It is generally thought that specific conditions initially encountered within granulomatous lesions, including oxygen-limitation and nitric oxide, inhibit aerobic respiration and induce the transition of M. tuberculosis into NRP for long-term survival during anaerobic dormancy. Aerobic and anaerobic respiration in M. tuberculosis is mediated in part by NADH dehydrogenases (NDH), enzymes which catalyze the oxidation of NADH to NAD+ with concomitant transfer of electrons to respiratory chain components. M. tuberculosis encodes one type-1 NDH and two type-2 NDHs. Recently, we identified a third predicted type-2 NDH (Rv1812c) that is regulated by determinants/conditions associated with M. tuberculosis persistence. Preliminary investigations described in this application indicate that Rv1812c encodes a type-2 NDH and participates in the resuscitation of M. tuberculosis from anaerobic dormancy. In addition, we provide bioinformatic evidence indicating that Rv1812c possesses unique structural, functional, and expression characteristics that distinguish it from the other two established type-2 NDHs (Ndh and NdhA) produced in M. tuberculosis. The two specific aims proposed in this application will allow us to investigate and compare the activities of the three type-2 NDHs produced in M. tuberculosis, and determine whether Rv1812c is required for M. tuberculosis NRP or its resuscitation from latency in vivo.