Lipoamide dehydrogenase of Staphylococcus aureus: nucleotide sequence and sequence analysis.

A complex of four proteins was previously isolated from Staphylococcus aureus. The complex had a strong interaction with membrane bound ribosomes, which suggested that it may be involved in protein secretion. However, the complex was identified as pyruvate dehydrogenase (PDH), which disproved the direct role of the complex in protein secretion. Here we report the nucleotide sequence of the last gene of the S. aureus pyruvate dehydrogenase operon, pdhD, which encodes lipoamide dehydrogenase (LPD). The pdhD gene encodes a protein of 468 amino acids, with a molecular mass of 49.5 kDa. The protein is closely related to other lipoamide dehydrogenases from bacteria and eukaryotes. The possible role of membrane bound lipoamide dehydrogenase is briefly discussed.