Abstract
Hyper thermophilic archaea not only tolerate high temperature but also operate its biochemical machineries, normally under these conditions. However, the structural signatures in proteins that answer for the hyper thermo-stability relative to its mesophilic homologue remains poorly understood. We present comparative analyses of sequences, structures and salt-bridges of prolyl-oligopeptidase from Pyrococcus furiosus (pfPOP - PDB ID: 5T88) and human (huPOP - PDB ID: 3DDU). A similar level of hydrophobic and hydrophilic residues in pfPOP and huPOP is observed. A low level of interactions between shell-waters and atom-types in pfPOP indicated hyper thermophilic features are negligible. Salt-bridge-forming-residues (sbfrs) are high in pfPOP's core and surface (pfPOP). Increased sbfrs largely indicate specific-electrostatic is important for thermo stability in pfPOP. Four classes of sbfrs are found namely positionally non-conservative (PNCS), conservative (PCS), unchanged (PU) and interchanged (PIC) type of substitutions. PNCS-sbfrs constitutes 28% and it is associated with the topology of pfPOP at high temperature. PCS helps to increase the salt-bridge population. It is also found that PU maintains similar salt-bridges at the active site and other binding sites while PIC abolishes mesophilic patterns.
Highlights
Native state of the protein is thermodynamically compromised
A salt bridge is defined as a specific electrostatic interaction between the side-chain of basic and acidic amino acids in native protein [2, 3]
Dataset: The 3D structure of pfPOP and its homologous huPOP are procured from the Research Collaboratory for Structural Bioinformatics (RCSB) protein data bank (PDB) [20]
Summary
Native state of the protein is thermodynamically compromised. Both favorable and unfavorable weak interactions are involved in this state of which salt bridge has been a major contributor to the thermostability [1]. A salt bridge is defined as a specific electrostatic interaction between the side-chain of basic and acidic amino acids in native protein [2, 3]. Comparative studies involving various physicochemical and structural parameters such as amino acids composition, oligomeric state, hydrophobicity, compactness, helical-content, salt-bridges, buried and exposed surface area and etc for homologous pairs of thermophilic and mesophilic protein showed insight into thermophilic adaptation [9] of which the increase of ion-pairs in thermophilic proteins have been somewhat general [10].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
