Structural Characterization of an ACP fromThermotoga maritima: Insights into Hyperthermal Adaptation.
Lee, Y., Jang, A., Jeong, M.C., Park, N., Park, J., Lee, W.C., Cheong, C., Kim, Y.(2020) Int J Mol Sci 21
- PubMed: 32283632 
- DOI: https://doi.org/10.3390/ijms21072600
- Primary Citation of Related Structures:  
6LVT, 6LVU - PubMed Abstract: 
Thermotoga maritima , a deep-branching hyperthermophilic bacterium, expresses an extraordinarily stable Thermotoga maritima acyl carrier protein ( Tm -ACP) that functions as a carrier in the fatty acid synthesis system at near-boiling aqueous environments. Here, to understand the hyperthermal adaptation of Tm -ACP, we investigated the structure and dynamics of Tm -ACP by nuclear magnetic resonance (NMR) spectroscopy. The melting temperature of Tm -ACP (101.4 °C) far exceeds that of other ACPs, owing to extensive ionic interactions and tight hydrophobic packing. The D59 residue, which replaces Pro/Ser of other ACPs, mediates ionic clustering between helices III and IV. This creates a wide pocket entrance to facilitate the accommodation of long acyl chains required for hyperthermal adaptation of the T. maritima cell membrane. Tm -ACP is revealed to be the first ACP that harbor an amide proton hyperprotected against hydrogen/deuterium exchange for I15. The hydrophobic interactions mediated by I15 appear to be the key driving forces of the global folding process of Tm -ACP. Our findings provide insights into the structural basis of the hyperthermal adaptation of ACP, which might have allowed T. maritima to survive in hot ancient oceans.
Organizational Affiliation: 
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.