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tRNAGlu increases the affinity of glutamyl-tRNA synthetase for its inhibitor glutamyl-sulfamoyl-adenosine, an analogue of the aminoacylation reaction intermediate glutamyl-AMP: mechanistic and evolutionary implications.

Author(s): Blais SP, Kornblatt JA, Barbeau X, Bonnaure G, Lagüe P, Chênevert R, Lapointe J

PLoS One. 2015;10(4):e0121043 Authors: Blais SP, Kornblatt JA, Barbeau X, Bonnaure G, Lagüe P, Chênevert R, Lapointe J

Article GUID: 25860020
The Energetics of Streptococcal Enolase Octamer Formation: The Quantitative Contributions of the Last Eight Amino Acids at the Carboxy-Terminus.

Author(s): Kornblatt JA, Quiros V, Kornblatt MJ

PLoS One. 2015;10(8):e0135754 Authors: Kornblatt JA, Quiros V, Kornblatt MJ

Article GUID: 26287818
The interaction of streptococcal enolase with canine plasminogen: the role of surfaces in complex formation.

Author(s): Balhara V, Deshmukh SS, Kálmán L, Kornblatt JA

PLoS One. 2014;9(2):e88395 Authors: Balhara V, Deshmukh SS, Kálmán L, Kornblatt JA

Article GUID: 24520380
The influence of truncating the carboxy-terminal amino acid residues of streptococcal enolase on its ability to interact with canine plasminogen.

Author(s): Deshmukh SS, Kornblatt MJ, Kornblatt JA

PLoS One. 2019;14(1):e0206338 Authors: Deshmukh SS, Kornblatt MJ, Kornblatt JA

Article GUID: 30653526
Title:The Energetics of Streptococcal Enolase Octamer Formation: The Quantitative Contributions of the Last Eight Amino Acids at the Carboxy-Terminus.
Authors:Kornblatt JA,  Quiros V,  Kornblatt MJ
Link:https://www.ncbi.nlm.nih.gov/pubmed/26287818?dopt=Abstract
DOI:10.1371/journal.pone.0135754
Category:PLoS One
PMID:26287818
Dept Affiliation: BIOLOGY
1 Centre for Structural and Functional Genomics, Department of Biology, Concordia University, Montréal, Canada.
2 Department of Biology, Concordia University, Montréal, Canada.
3 Department of Chemistry and Biochemistry, Concordia University, Montréal, Canada.

Description:

The Energetics of Streptococcal Enolase Octamer Formation: The Quantitative Contributions of the Last Eight Amino Acids at the Carboxy-Terminus.

PLoS One. 2015;10(8):e0135754

Authors: Kornblatt JA, Quiros V, Kornblatt MJ

Abstract

The enolase produced by Streptococcus pyogenes is a homo-octamer whose overall shape resembles that of a donut. The octamer is best described as a tetramer of dimers. As such, it contains two types of interfaces. The first is common to almost all enolases as most enolases that have been studied are dimers. The second is unique to the octamers and includes residues near the carboxy-terminus. The primary sequence of the enolase contains 435 residues with an added 19 as an N-terminal hexahistine tag. We have systematically truncated the carboxy-terminus, individually removing the first 8 residues. This gave rise to a series of eight structures containing respectively, 435, 434, 433, 432, 431, 430, 429 and 427 residues. The truncations cause the protein to gradually dissociate from octamers to enzymatically inactive monomers with very small amounts of intermediate tetramers and dimers. We have evaluated the contributions of the missing residues to the monomer/octamer equilibrium using a combination of analytical ultracentrifugation and activity assays. For the dissociation reaction, octamer <== ==> 8 monomer truncation of all eight C-terminal residues resulted in a diminution in the standard Gibbs energy of dissociation of about 59 kJ/mole of octamer relative to the full length protein. Considering that this change is spread over eight subunits, this translates to a change in standard Gibbs interaction energy of less than 8 kJ/mole of monomer distributed over the eight monomers. The resulting proteins, containing 434, 433, 432, 431, 430, 429 and 427 residues per monomer, showed intermediate free energies of dissociation. Finally, three other mutations were introduced into our reference protein to establish how they influenced the equilibrium. The main importance of this work is it shows that for homo-multimeric proteins a small change in the standard Gibbs interaction energy between subunits can have major physiological effects.

PMID: 26287818 [PubMed - indexed for MEDLINE]