CEFOBI   05405
CENTRO DE ESTUDIOS FOTOSINTETICOS Y BIOQUIMICOS
Unidad Ejecutora - UE
artículos
Título:
Identification of domains implicated in tetramerization and malate inhibition of maize C4 NADP-malic enzyme by analysis of chimerical proteins
Autor/es:
ENRIQUE DETARSIO; CLARISA ALVAREZ; MARIANA SAIGO; CARLOS ANDREO; MARÍA FABIANA DRINCOVICH
Revista:
JOURNAL OF BIOLOGICAL CHEMISTRY
Editorial:
The American Society for Biochemistry and Molecular Biology
Referencias:
Año: 2007 vol. 282 p. 6053 - 6060
ISSN:
0021-9258
Resumen:
C4 photosynthetic NADP-malic enzyme has evolved from non-C4 isoforms and gained unique kinetic and structural properties during this process. In order to identify the domains responsible for the structural and kinetic differences between maize C4- and non-C4 NADP-ME several chimeras between these isoforms were constructed and analysed. By using this approach, we found that the region flanked by amino acid residues 102 and 247 is critical for the tetrameric state of C4 NADP-ME. In this way, the oligomerization strategy of these NADP-ME isoforms differs markedly from the one that present non-plant NADP-ME with known crystal structures. On the other hand, the region from residue 248 to the C terminal end of the C4 isoform is involved in the inhibition by high malate concentrations at pH 7.0. The inhibition pattern of the C4-NADP-ME and some of the chimeras suggested an allosteric site responsible for such behaviour. This pH-dependent inhibition could be important for regulation of the C4 isoform in vivo, with the enzyme presenting maximum activity while photosynthesis is in progress