Data/hora: 04/06/2024 03:46:21

Biblioteca(s): | Embrapa Milho e Sorgo.
Data corrente: | 01/12/2016
Data da última atualização: | 01/12/2016
Autoria: | GIUSEPPE, P. O. de; SANTOS, M. L. dos; SOUSA, S. M. de; KOCH, K. E.; YUNES, J. A.; APARICIO, R.; MURAKAMI, M. T.
Afiliação: | Priscila Oliveira de Giuseppe, Centro Nacional de Pesquisa em Energia e Materiais - CNPEM; Marcelo Leite dos Santos, Universidade de Campinas; SYLVIA MORAIS DE SOUSA TINOCO, CNPMS; Karen E. Koch, Universidade da Florida; José Andrés Yunes, Universidade de Campinas; Ricardo Aparicio, Universidade de Campinas; Mario Tyago Murakami, Centro Nacional de Pesquisa em Energia e Materiais - CNPEM.
Título: | A comparative structural analysis reveals distinctive features of cofactor binding and substrate specificity in plant aldo-keto reductases.
Ano de publicação: | 2016
Fonte/Imprenta: | Biochemical and Biophysical Research Communications, v. 474, p. 696-701, 2016.
DOI: | 10.1016/j.bbrc.2016.05.011
Idioma: | Inglês
Conteúdo: | Plant aldo-keto reductases of the AKR4C subfamily play key roles during stress and are attractive targets for developing stress-tolerant crops. However, these AKR4Cs show little to no activity with previouslyenvisioned sugar substrates. We hypothesized a structural basis for the distinctive cofactor binding and substrate specificity of these plant enzymes. To test this, we solved the crystal structure of a novel AKR4C subfamily member, the AKR4C7 from maize, in the apo form and in complex with NADPþ. The binary complex revealed an intermediate state of cofactor binding that preceded closure of Loop B, and also indicated that conformational changes upon substrate binding are required to induce a catalyticallyfavorable conformation of the active-site pocket. Comparative structural analyses of homologues (AKR1B1, AKR4C8 and AKR4C9) showed that evolutionary redesign of plant AKR4Cs weakened interactions that stabilize the closed conformation of Loop B. This in turn decreased cofactor affinity and altered configuration of the substrate-binding site. We propose that these structural modifications contribute to impairment of sugar reductase activity in favor of other substrates in the plant AKR4C subgroup, and that catalysis involves a three-step process relevant to other AKRs.
Thesagro: | Enzima; Reductase.
Categoria do assunto: | S Ciências Biológicas
Registro original: | Embrapa Milho e Sorgo (CNPMS)
Exemplares: | CNPMS - (27490-1) - UPC - AP - DD -  -  -  - DIS