INVESTIGADORES
IGLESIAS Alberto Alvaro
artículos
Título:
ADPglucose Pyrophosphorylase's N-terminus: Structural Role in Allosteric Regulation
Autor/es:
C.M. BEJAR, M.A. BALLICORA, A.A. IGLESIAS, J. PREISS
Revista:
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Editorial:
Academic Press
Referencias:
Año: 2006 vol. 343 p. 216 - 221
ISSN:
0006-291X
Resumen:
AbstractWe studied the functional role of the Escherichia coli ADPglucose pyrophosphorylase?s N-terminus in allosteric regulation, and the particular effects caused by its length. Small truncated mutants were designed, and those lacking up to 15-residues were active and highly purified for further kinetic analyses. ND3 and ND7 did not change the kinetic parameters with respect to the wild-type. ND11 and ND15 enzymes were insensitive to allosteric regulation and highly active in the absence of the activator. Co-expression of two polypeptides corresponding to the N- and C-termini generated an enzyme with activation properties lower than those of the wild-type [C.M. Bejar, M.A. Ballicora, D.F. Go´mez Casati, A.A. Iglesias, J. Preiss, The ADPglucose pyrophosphorylase from Escherichia coli comprises two tightly bound distinct domains, FEBS Lett. 573 (2004) 99?104]. Here, we characterized a ND15 co-expression mutant, in which the allosteric regulation was restored to wild-type levels. Unusual allosteric effects caused by either an N-terminal truncation or co-expression of individual domains may respond to structural changes favoring an up-regulated or a down-regulated conformation rather than specific activator or inhibitor sites? disruption. 2006 Elsevier Inc. All rights reserved.Keywords: Glycogen synthesis; ADPglucose pyrophosphorylase; Allosteric regulation; N-terminus deletion