Amino Acid Residues Critical for the Specificity for Betaine Aldehyde of the Plant ALDH10 Isoenzyme Involved in the Synthesis of Glycine Betaine
Por:
Diaz-Sanchez, AG, Gonzalez-Segura, L, Mujica-Jimenez, C, Rudino-Pinera, E, Montiel, C, Martinez-Castilla, LP, Munoz-Clares, RA
Publicada:
1 abr 2012
Resumen:
Plant Aldehyde Dehydrogenase10 (ALDH10) enzymes catalyze the oxidation of omega-primary or omega-quaternary aminoaldehydes, but, intriguingly, only some of them, such as the spinach (Spinacia oleracea) betaine aldehyde dehydrogenase (SoBADH), efficiently oxidize betaine aldehyde (BAL) forming the osmoprotectant glycine betaine (GB), which confers tolerance to osmotic stress. The crystal structure of SoBADH reported here shows tyrosine (Tyr)-160, tryptophan (Trp)-167, Trp-285, and Trp-456 in an arrangement suitable for cation-pi interactions with the trimethylammonium group of BAL. Mutation of these residues to alanine (Ala) resulted in significant K-m (BAL) increases and V-max/K-m (BAL) decreases, particularly in the Y160A mutant. Tyr-160 and Trp-456, strictly conserved in plant ALDH10s, form a pocket where the bulky trimethylammonium group binds. This space is reduced in ALDH10s with low BADH activity, because an isoleucine (Ile) pushes the Trp against the Tyr. Those with high BADH ac
Filiaciones:
Diaz-Sanchez, AG:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Gonzalez-Segura, L:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Mujica-Jimenez, C:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Rudino-Pinera, E:
Univ Nacl Autonoma Mexico, Inst Biotecnol, Dept Med Mol & Bioproc, Cuernavaca 62250, Morelos, Mexico
Montiel, C:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Martinez-Castilla, LP:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Munoz-Clares, RA:
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
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