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Alkaline pH-dependent differential unfolding characteristics of mesophilic and thermophilic homologs of dimeric serine hydroxymethyltransferase.
Biochim Biophys Acta. 2010 Jun; 1804(6):1294-300.BB

Abstract

Environmental variables such as pH can significantly influence the folding and stability of a protein molecule. In the present investigation, we compared the alkaline pH-induced unfolding of two homologous serine hydroxymethyltransferase from mesophilic Bacillus subtilis (bsSHMT) and thermophilic Bacillus stearothermophilus (bstSHMT) using various biophysical techniques. The thermophilic enzyme bstSHMT was found to be more resistant to alkaline denaturation compared to its mesophilic counterpart, bsSHMT. Unfolding studies using domain-swapped chimera, constructed by swapping the C-terminal domain of these two wild-type proteins, revealed that C-terminal domain plays a pivotal role in the folding, stability and subunit interaction of these proteins. Primary amino acid sequence analysis of the proteins showed that bsSHMT has six unconserved lysine residues in C-terminal domain, which are absent in bstSHMT. Chemical modification of lysine side chains resulted in stabilization of monomers, only in case of bsSHMT. Moreover, comparison between homology model of bsSHMT with the crystal structure of bstSHMT revealed that a small stretch of 11 amino acids at the end of C-terminal domain was found protruding outside the molecule as a flexible coiled structure in bsSHMT. Taken together these findings suggest that possibly the presence of these non-identical lysine moieties and a small extension of C-terminal domain may be responsible for low stability of bsSHMT under alkaline pH condition.

Authors+Show Affiliations

Division of Radiation Biosciences, Institute of Nuclear Medicine and Allied Sciences, Delhi 110 054, India. anant.bhatt@indiatimes.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20152942

Citation

Bhatt, Anant Narayan, et al. "Alkaline pH-dependent Differential Unfolding Characteristics of Mesophilic and Thermophilic Homologs of Dimeric Serine Hydroxymethyltransferase." Biochimica Et Biophysica Acta, vol. 1804, no. 6, 2010, pp. 1294-300.
Bhatt AN, Bhakuni V, Kumar A, et al. Alkaline pH-dependent differential unfolding characteristics of mesophilic and thermophilic homologs of dimeric serine hydroxymethyltransferase. Biochim Biophys Acta. 2010;1804(6):1294-300.
Bhatt, A. N., Bhakuni, V., Kumar, A., Khan, M. Y., & Siddiqi, M. I. (2010). Alkaline pH-dependent differential unfolding characteristics of mesophilic and thermophilic homologs of dimeric serine hydroxymethyltransferase. Biochimica Et Biophysica Acta, 1804(6), 1294-300. https://doi.org/10.1016/j.bbapap.2010.01.023
Bhatt AN, et al. Alkaline pH-dependent Differential Unfolding Characteristics of Mesophilic and Thermophilic Homologs of Dimeric Serine Hydroxymethyltransferase. Biochim Biophys Acta. 2010;1804(6):1294-300. PubMed PMID: 20152942.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Alkaline pH-dependent differential unfolding characteristics of mesophilic and thermophilic homologs of dimeric serine hydroxymethyltransferase. AU - Bhatt,Anant Narayan, AU - Bhakuni,Vinod, AU - Kumar,Ashutosh, AU - Khan,M Yahiya, AU - Siddiqi,Mohammad Imran, Y1 - 2010/02/10/ PY - 2009/06/03/received PY - 2010/01/27/revised PY - 2010/01/29/accepted PY - 2010/2/16/entrez PY - 2010/2/16/pubmed PY - 2010/5/26/medline SP - 1294 EP - 300 JF - Biochimica et biophysica acta JO - Biochim Biophys Acta VL - 1804 IS - 6 N2 - Environmental variables such as pH can significantly influence the folding and stability of a protein molecule. In the present investigation, we compared the alkaline pH-induced unfolding of two homologous serine hydroxymethyltransferase from mesophilic Bacillus subtilis (bsSHMT) and thermophilic Bacillus stearothermophilus (bstSHMT) using various biophysical techniques. The thermophilic enzyme bstSHMT was found to be more resistant to alkaline denaturation compared to its mesophilic counterpart, bsSHMT. Unfolding studies using domain-swapped chimera, constructed by swapping the C-terminal domain of these two wild-type proteins, revealed that C-terminal domain plays a pivotal role in the folding, stability and subunit interaction of these proteins. Primary amino acid sequence analysis of the proteins showed that bsSHMT has six unconserved lysine residues in C-terminal domain, which are absent in bstSHMT. Chemical modification of lysine side chains resulted in stabilization of monomers, only in case of bsSHMT. Moreover, comparison between homology model of bsSHMT with the crystal structure of bstSHMT revealed that a small stretch of 11 amino acids at the end of C-terminal domain was found protruding outside the molecule as a flexible coiled structure in bsSHMT. Taken together these findings suggest that possibly the presence of these non-identical lysine moieties and a small extension of C-terminal domain may be responsible for low stability of bsSHMT under alkaline pH condition. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/20152942/Alkaline_pH_dependent_differential_unfolding_characteristics_of_mesophilic_and_thermophilic_homologs_of_dimeric_serine_hydroxymethyltransferase_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1570-9639(10)00039-7 DB - PRIME DP - Unbound Medicine ER -