초록
<P><I>Thermobifida fusca</I> is a thermophilic actinobacterium. <I>T. fusca</I> muC obtained by adaptive evolution preferred yeast extract to ammonium sulfate for accumulating malic acid and ammonium sulfate for cell growth. We did transcriptome analysis of <I>T. fusca</I> muC on Avicel and cellobiose with addition of ammonium sulfate or yeast extract, respectively by RNAseq. The transcriptional results indicate that ammonium sulfate induced the transcriptions of the genes related to carbohydrate metabolisms significantly more than yeast extract. Importantly, <I>Tfu_2487</I>, encoding histidine-containing protein (HPr), didn’t transcribe on yeast extract at all, while it transcribed highly on ammonium sulfate. In order to understand the impact of HPr on malate production and cell growth of the muC strain, we deleted <I>Tfu_2487</I> to get a mutant strain: muCΔ2487, which had 1.33 m<B>o</B>le/mole-glucose equivalent malate yield, much higher than that on yeast extract. We then developed an <I>E. coli</I>-T. fusca shuttle plasmid for over-expressing HPr in muCΔ2487, a strain without HPr background, forming the muCΔ2487S strain. The muCΔ2487S strain had a much lower malate yield but faster cell growth than the muC strain. The results of both mutant strains confirmed that HPr was the key regulatory protein for <I>T. fusca</I>’s metabolisms on nitrogen sources.</P>