Artículos
Título:
Structural and biochemical insight into glycogenin inactivation by the glycogenosis-causing T82M mutation
Autor/es:
CARRIZO, M.E.; ROMERO, J.M.; ISSOGLIO, F.M.; CURTINO, J.A.
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 586 p. 254 - 254
Resumen:
he X-ray structure of rabbit glycogenin containing the T82M (T83M
according to previous authors amino acid numbering) mutation causing
glycogenosis showed the loss of Thr82 hydrogen bond to Asp162, the
residue involved in the activation step of the glucose transfer reaction
mechanism. Autoglucosylation, maltoside transglucosylation and
UDP-glucose hydrolyzing activities were abolished even though affinity
and interactions with UDP-glucose and positioning of Tyr194 acceptor
were conserved. Substitution of Thr82 for serine but not for valine
restored the maximum extent of autoglucosylation as well as
transglucosylation and UDP-glucose hydrolysis rate. Results provided
evidence sustaining the essential role of the lost single hydrogen bond
for UDP-glucose activation leading to glycogenin-bound glycogen primer
synthesis.