DNA sequences of genes encoding Acinetobacter calcoaceticus protocatechuate 3,4-dioxygenase: evidence indicating shuffling of genes and of DNA sequences within genes during their evolutionary divergence.

摘要: The DNA sequence of a 2,391-base-pair HindIII restriction fragment Acinetobacter calcoaceticus containing the pcaCHG genes is reported. reveals that A. pca genes, encoding enzymes required for protocatechuate metabolism, are arranged in single transcriptional unit, pcaEFDBCHG, whereas homologous differently Pseudomonas putida. pcaG and pcaH represent separate reading frames respectively alpha beta subunits 3,4-dioxygenase (EC 1.13.1.3); previously designation, pcaA, had been used to this enzyme. protein appear share common ancestry with each other catechol 1,2-dioxygenases from P. Marked conservation amino acid observed region two histidyl residues tyrosyl ligate iron within oxygenase. In some regions aligned oxygenase sequences, sequences be conserved at level beyond extent might have demanded by selection protein. regions, divergence appears achieved substitution one genetic segment into another. results interpreted consequence exchange gene conversion between slipped strands during evolutionary divergence; mismatch repair may contribute maintenance divergent genes.