Coregulation by phenylacetyl-coenzyme A-responsive PaaX integrates control of the upper and lower pathways for catabolism of styrene by Pseudomonas sp strain Y2
Coregulation by phenylacetyl-coenzyme A-responsive PaaX integrates control of the upper and lower pathways for catabolism of styrene by Pseudomonas sp strain Y2
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DOI：
10.1128/jb.00176-06
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发表时间：
2006-07-01
影响因子：
3.2
通讯作者：
Perera, Julian
中科院分区：
文献类型：
--
作者：
del Peso-Santos, Teresa;Bartolome-Martin, David;Perera, Julian
The P-styA promoter of Pseudomonas sp. strain Y2 controls expression of the styABCD genes, which are required for the conversion of styrene to phenylacetate, which is further catabolized by the products of two paa gene clusters. Two PaaX repressor proteins (PaaX1 and PaaX2) regulate transcription of the paa gene clusters of this strain. In silico analysis of the P-styA promoter region revealed a sequence located just within styA that is similar to the reported PaaX binding sites of Escherichia coli and the proposed PaaX binding sites of the paa genes of Pseudomonas species. Here we show that protein extracts from some Pseudomonas strains that have paaX genes, but not from a paaX mutant strain, can bind and retard the migration of a P-styA specific probe. Purified maltose-binding protein (MBP)-PaaX1 fusion protein specifically binds the P-styA promoter proximal PaaX site, and this binding is eliminated by the addition of phenylacetyl-coenzyme A. The sequence protected by MBP-PaaX1 binding was defined by DNase I footprinting. Moreover, MBP-PaaX1 represses transcription from the P-styA promoter in a phenyl acetyl-coenzyme A-dependent manner in vitro. Finally, the inactivation of both paaX gene copies of Pseudomonas sp. strain Y2 leads to a higher level of transcription from the P-styA promoter, while heterologous expression of the PaaX1 in E. coli greatly decreases transcription from the P-styA promoter. These findings reveal a control mechanism that integrates regulation of styrene catabolism by coordinating the expression of the styrene upper catabolic operon to that of the paa-encoded central pathway and support a role for PaaX as a major regulatory protein in the phenylacetyl-coenzyme A catabolon through its response to the levels of this central metabolite.
