Computational Studies of the Molecular Basis of Natural and Acquired Resistance to Extremes in Microbes

项目总结 我们的长期目标是了解微生物如何能够经受住 温度、压力和化学组成(P-T-X)，通过确定大分子如何 组成微生物的结构被保存下来。我们的重点是高压的影响，这是 人们对温度的了解要少得多。由于高压方法越来越多地被使用 对于食品保鲜来说，了解压力的影响对人类的健康和福利非常重要。 令人不安的是，一些中温微生物似乎能够承受~10kbar的压力，而嗜压微生物 在最大压力为~1.1kbar的情况下，已经发现了(喜压)微生物。确定什么 压力会破坏蛋白质在类细胞条件下的结构将有助于确定极限压力 微生物可以在那里生长。 我们拟议工作的目标是通过以下方式了解P-T效应对蛋白质的相互作用 检测嗜冷菌(嗜冷菌)和嗜热菌(嗜热菌)的酶，这两种嗜冷菌也是嗜压菌 在不同的P-T。根据我们之前对一种嗜压嗜冷酶的研究，微生物可能主要是 适应温度而不是高压，嗜冷菌产生的酶 比那些来自嗜热菌的更脆弱。拟议的研究将扩大细菌的生长温度范围。 微生物的来源是嗜压性嗜热酶。他们还将解决压电体的影响， 这是一种渗透分子，可以保护蛋白质免受压力影响。我们的方法是使用分子 动力学、计算机模拟和生物物理实验。 我们的具体目标是： 目的1.了解其他嗜冷酶的亲压性。 目的2.了解嗜热酶的亲压性。 目的3.了解压电体如何改变压力对蛋白质的影响。

PROJECT SUMMARY Our long-term goal is to understand how microbes are able to withstand remarkable extremes of temperature, pressure, and chemical composition (P-T-X), by determining how the macromolecular structures comprising the microbes are preserved. Our focus is on the effects of high pressure, which are much less understood than those of temperature. Since high-pressure methods are increasingly being used for food preservation, understanding the effects of pressure is important for human health and welfare. Disturbingly, some mesophilic microbes appear to able to withstand ~10 kbar pressures, while piezophilic (pressure-loving) microbes have been found at maximum pressures of ~1.1 kbar. Determining what pressures will disrupt structures of proteins in cell-like conditions will help to define the limiting pressures that microbes can grow at. Our goal for the proposed work is to understand the interplay of P-T effects on proteins by examining enzymes from psychrophiles (cold-loving) and thermophiles (hot-loving) that are also piezophilic at different P-T. Based on our previous work on a piezophilic psychrophile enzyme, microbes may be mainly adapted for temperature rather than high pressure and enzymes from psychrophiles appear much more fragile than those from thermophiles. The proposed studies will expand the range of growth temperatures of the source organisms to piezophilic thermophile enzymes. They will also address the effects of piezolytes, which are osmolytes that protect against pressure effects, on proteins. Our approach uses molecular dynamics computer simulations and biophysical experiments. Our specific aims are to: Aim 1. Understand piezophilicity in other psychrophile enzymes. Aim 2. Understand piezophilicity in thermophile enzymes. Aim 3. Understand how piezolytes change pressure effects on proteins.