Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10536914 | Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics | 2014 | 8 Pages |
Abstract
The archaeal non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN, EC 1.2.1.9) is a highly allosteric enzyme activated by glucose 1-phosphate (Glc1P). Recent kinetic analyses of two GAPN homologs from Sulfolobales show different allosteric behaviors toward the substrate glyceraldehyde-3-phosphate (GAP) and the allosteric effector Glc1P. In GAPN from Sulfolobus tokodaii (Sto-GAPN), Glc1P-induced activation follows an increase in affinity for GAP rather than an increase in maximum velocity, whereas in GAPN from Sulfolobus solfataricus (Sso-GAPN), Glc1P-induced activation follows an increase in maximum velocity rather than in affinity for GAP. To explore the molecular basis of this difference between Sto-GAPN and Sso-GAPN, we generated 14 mutants and 2 chimeras. The analyses of chimeric GAPNs generated from regions of Sto-GAPN and Sso-GAPN indicated that a 57-residue module located in the subunit interface was clearly involved in their allosteric behavior. Among the point mutations in this modular region, the Y139R variant of Sto-GAPN no longer displayed a sigmoidal K-type-like allostery, but instead had apparent V-type allostery similar to that of Sso-GAPN, suggesting that the residue located in the center of the homotetramer critically contributes to the allosteric behavior.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Fumiaki Ito, Masayuki Miyake, Shinya Fushinobu, Shugo Nakamura, Kentaro Shimizu, Takayoshi Wakagi,