K-098. FolP2, A Functionally Encoded Dihydropteroate Synthase in Corynebacterium glutamicum ATCC 13032

S-K. Lee, E-K. Shin, S-H. Cho, H-G. Rhie;
Kyunghee Univ., Seoul, REPUBLIC OF KOREA.

A search of the “Cluster of Orthologous Groups of proteins” (COG) database showed the presence of two putative dihydropteroate synthase(DHPS) genes, folP1 and folP2, in Corynebacterium glutamicum ATCC 13032. To determine if the additional folP2 contained functional open reading frame, folP2 was cloned into E. coli C600ΔfolP::Kmr strain. While E. coli C600(ΔfolP::Kmr) was not able to grow in minimal medium without supply of dihydropteroate, the recombinant plasmid pUC18-folP2 functionally complemented growth defect on minimal medium like E. coli C60 (ΔfolP::Kmr) containing folP1 did. E. coli C600 and recombinant strain were tested for growth on Mueller-Hinton agar medium containing various concentrations of dapsone. Growth of recombinant E.coli C600(ΔfolP::Kmr) containing folP2 was not inhibited at 250 μg of dapsone/ml, which represents a same resistance to dapsone of C. glutamicum DHPS (folP2) compared to E.coli DHPS. Reverse transcription-PCR analysis also revealed that folP1 and folP2 were transcribed in C. glutamicum. These results indicated that Corynebacterium glutamicum contained two functional DHPSs to catalyze the condensation of p-aminobenzoic acid (pABA) with 6-hydroxymethyl-7,8-dihydropterin pyrophosphate (HPOPP) to form 7,8-dihydropteroate and pyrophosphate.