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X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
A monomeric TIM-barrel structure from Pyrococcus furiosus is optimized for extreme temperatures
Heidi Repo1, Jesper S Oeemig, Janica Djupsjöbacka
1Institute of Biotechnology, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland.
Acta Crystallographica. Section D, Biological Crystallography
|October 24, 2012
Summary
The structure of phosphoribosyl anthranilate isomerase (TrpF) from Pyrococcus furiosus reveals a unique monomeric TIM-barrel fold. This archaeal enzyme exhibits enhanced stability through increased ion pairs and optimized interactions, offering potential for protein engineering.
Area of Science:
- Biochemistry
- Structural Biology
- Archaea Biology
Background:
- Phosphoribosyl anthranilate isomerase (TrpF) is crucial in the tryptophan biosynthesis pathway.
- Understanding enzyme structure-function relationships, especially in thermophiles, is key for biotechnological applications.
- The hyperthermophilic archaeon Pyrococcus furiosus provides a model for studying thermostable proteins.
Purpose of the Study:
- To determine the high-resolution structure of TrpF from Pyrococcus furiosus (PfTrpF).
- To compare the structural features of PfTrpF with known thermophilic and mesophilic TrpF enzymes.
- To elucidate the molecular mechanisms underlying the thermostability of PfTrpF.
Main Methods:
- X-ray crystallography was used to determine the three-dimensional structure of PfTrpF at 1.75 Å resolution.
- Comparative structural analysis was performed between PfTrpF, other thermophilic TrpF proteins, and a mesophilic homolog (EcTrpF).
- Analysis of residue composition, ion pairing, and water molecule interactions was conducted.
Main Results:
- PfTrpF adopts a monomeric TIM-barrel fold, distinct from the dimeric structures of other thermophilic TrpF proteins.
- Thermophilic TrpF structures, including PfTrpF, possess a higher proportion of ion pairs and charged residues compared to mesophilic EcTrpF.
- PfTrpF utilizes direct side-chain-main-chain interactions, replacing conserved structural water molecules, contributing to its stability.
Conclusions:
- The monomeric PfTrpF structure reveals unique adaptations for thermostability, including optimized internal interactions.
- The findings highlight the role of increased ion pairing and specific residue interactions in stabilizing the TIM-barrel fold at high temperatures.
- PfTrpF represents a thermodynamically stable and entropically optimized enzyme, suitable for protein engineering and industrial applications.
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