The evolution of low-temperature adapted enzymes
适应低温的酶的进化
- 关键词：
- 来源：
- EurekAlert
- 类型：
- 前沿资讯
- 语种：
- 英语
- 原文发布日期：
- 2025-03-25
- 摘要：
- A research team led by Professor Satoshi Akanuma from Waseda University, Japan, in collaboration with Assistant Professor Sota Yagi from Waseda University, Dr. Subrata Dasgupta, and Dr. Shunsuke Tagami from the RIKEN Center for Biosystems Dynamics Research, investigated the evolutionary improvement of IPMDH activity at low temperatures. They traced its evolution from the enzyme of the most ancient thermophilic common ancestor to the mesophilic bacterium Escherichia coli using ASR. Their study was published online in the journal Protein Science on February 19, 2025.“We reconstructed 11 intermediate ancestral enzymes along the evolutionary trajectory connecting the last common bacterial ancestor and E. coli IPMDH (EcIPMDH),” explains Akanuma. “After that, we analyzed changes in enzyme activity at each evolutionary stage, especially improvements in catalytic activity at low temperatures.” They observed a notable increase in catalytic activity at 25 °C, which did not follow a gradual, linear pattern. Instead, a dramatic improvement occurred between the fifth (Anc05) and sixth (Anc06) intermediate ancestors.What caused this sudden boost in enzymatic efficiency? To find the underlying molecular mechanisms, the researchers compared the amino acid sequences of the ancestral enzymes and used site-directed mutagenesis, a technique that allows precise alterations to DNA and protein sequences. They identified three key amino acid substitutions that significantly enhanced catalytic activity at 25 °C. Surprisingly, these mutations occurred far from the active site, challenging the previous belief that temperature adaptation is primarily driven by active-site modifications. Molecular dynamics simulations revealed a key structural shift between Anc05 and Anc06. While Anc05 remained in an open conformation, Anc06 could adopt a partially closed conformation, reducing activation energy and enhancing enzymatic efficiency at low temperatures. This transition occurred 2.5–2.1 billion years ago, coinciding with the Great Oxidation Event, which led to a sharp decline in atmospheric methane and global cooling. The researchers suggest that this climate shift may have driven the adaptation of enzymes to lower temperatures. By identifying key mutations that enhance enzyme efficiency, ASR provides valuable insights into how life evolved in response to Earth's changing environment. “Applying this approach to various enzymes is expected to reveal how organisms and their enzymes have evolved in response to Earth's environmental changes over the past four billion years,” Akanuma concluded.
- 所属专题：
- 173
