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dc.contributor.author
Gomez Casati, Diego Fabian
dc.contributor.author
Aon, M.A.
dc.contributor.author
Iglesias, Alberto Alvaro
dc.date.available
2019-10-11T12:06:09Z
dc.date.issued
2000-08
dc.identifier.citation
Gomez Casati, Diego Fabian; Aon, M.A.; Iglesias, Alberto Alvaro; Kinetic and structural analysis of the ultrasensitive behaviour of cyanobacterial adp-glucose pyrophosphorylase; Portland Press; Biochemical Journal; 350; 1; 8-2000; 139-147
dc.identifier.issn
0264-6021
dc.identifier.uri
http://hdl.handle.net/11336/85663
dc.description.abstract
The kinetic and (supra)molecular properties of the ultrasensitive behaviour of ADP-glucose pyrophosphorylase (AGPase) from Anabaena PCC 7120 (a cyanobacterium) were exhaustively studied. The response of the enzyme toward the allosteric activator 3-phosphoglycerate (3PGA) occurs with ultrasensitivity as a consequence of the cross-talk with the inhibitor P1. Molecular 'crowding' renders AGPase more sensitive to the interplay between the allosteric regulators and, consequently, enhances the ultrasensitive response. In crowded media, and when orthophosphate is present, the activation kinetics of the enzyme with 3PGA proceed with increased co-operativity and reduced affinity toward the activator. Under conditions of ultrasensitivity, the enzyme's maximal activation takes place in a narrow range of 3PGA concentrations. Moreover, saturation kinetics of the enzyme with respect to its substrates, glucose 1-phosphate and ATP, were different at low or high 3PGA levels in crowded media. Only under the latter conditions did AGPase exhibit discrimination between low or high levels of the activator, which increased the affinity toward the substrates and the maximal activity reached by the enzyme. Studies of fluorescence emission of tryptophan residues, fourth-derivative spectroscopy and size-exclusion chromatography indicated that the ultrasensitive behaviour is correlated with intramolecular conformational changes induced in the tertiary structure of the homotetrameric enzyme. The results suggest a physiological relevance of the ultrasensitive response of AGPase in vivo, since the enzyme could be subtly sensing changes in the levels of allosteric regulators and substrates, and thus determining the flux of metabolites toward synthesis of storage polysaccharides.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Portland Press
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
ANABAENA PCC 7120
dc.subject
ENZYME STRUCTURE AND REGULATION
dc.subject
GLYCOGEN AND STARCH BIOSYNTHESIS
dc.subject
MOLECULAR CROWDING
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ULTRASENSITIVITY
dc.subject.classification
Bioquímica y Biología Molecular
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Ciencias Biológicas
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
dc.title
Kinetic and structural analysis of the ultrasensitive behaviour of cyanobacterial adp-glucose pyrophosphorylase
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2019-10-10T19:33:57Z
dc.journal.volume
350
dc.journal.number
1
dc.journal.pagination
139-147
dc.journal.pais
Reino Unido
dc.journal.ciudad
Londres
dc.description.fil
Fil: Gomez Casati, Diego Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina
dc.description.fil
Fil: Aon, M.A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina
dc.description.fil
Fil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina
dc.journal.title
Biochemical Journal
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1042/0264-6021:3500139
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