RESUMO
We have isolated the Pichia sorbitophila LYS2 (PsLYS2) gene by complementation of a lys2 Saccharomyces cerevisiae mutant. The sequenced DNA fragment contains a putative ORF of 4197 bp and the deduced translation product shares a global identity of 66% and 58% to the Lys2 protein homologues of Candida albicans and S. cerevisiae, respectively. Analysis of PsLYS2 sequence suggests that, similarly to S. cerevisiae LYS2, it codes for a polypeptide having two separate enzymatic activities which reside in different domains of the protein, including an adenylate domain, an acyl-carrier site and a short-chain reductase domain. Several GCN4- and NIT2-binding motifs have been matched in the promotor sequence of PsLYS2. In addition, upstream of the sequenced PsLYS2 sequence, we have found the 3'-terminal half of a gene of same orientation encoding a RAD16-like protein, a genomic organization similar to that of C. albicans.
Assuntos
Aldeído Oxirredutases/química , Aldeído Oxirredutases/genética , Clonagem Molecular , Genes Fúngicos , Pichia/genética , Aldeído Oxirredutases/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Candida albicans/enzimologia , Candida albicans/genética , Códon , Teste de Complementação Genética , L-Aminoadipato-Semialdeído Desidrogenase , Lisina/biossíntese , Dados de Sequência Molecular , Mutação , Fases de Leitura Aberta , Pichia/enzimologia , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Cell-to-cell movement of beet necrotic yellow vein virus (BNYVV) requires three proteins encoded by a triple gene block (TGB) on viral RNA 2. A BNYVV RNA 3-derived replicon was used to express movement proteins to functionally substitute for the BNYVV TGB proteins was tested by coinoculation of TGB-defective BNYVV with the various replicons to Chenopodium quinoa. Trans-heterocomplementation was successful with the movement protein (P30) of tobacco mosaic virus but not with the tubule-forming movement proteins of alfalfa mosaic virus and grapevine fanleaf virus. Trans-complementation of BNYVV movement was also observed when all three TGB proteins of the distantly related peanut clump virus were supplied together but not when they were substituted for their BNYVV counterparts one by one. When P30 was used to drive BNYVV movement in trans, accumulation of the first TGB protein of BNYVV was adversely affected by null mutations in the second and third TGB proteins. Taken together, these results suggest that highly specific interactions among cognate TGB proteins are important for their function and/or stability in planta.
