Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon-Gun, Chungbuk, Republic of Korea.
FEBS Lett. 2010 Feb 19;584(4):675-80. doi: 10.1016/j.febslet.2009.12.059. Epub 2010 Jan 19.
Human holocarboxylase synthetase shows a high degree of sequence homology in the catalytic domain with bacterial biotin ligases such as Escherichia coli BirA, but differs in the length and sequence of the N-terminus. Despite several studies having been undertaken on the N-terminal region of hHCS, the role of this region remains unclear. We determined the structure of the N-terminal domain of hHCS by limited proteolysis and showed that this domain has a crucial effect on the enzymatic activity. The domain interacts not only with biotin acceptor protein, but also with the catalytic domain of hHCS, as shown by nuclear magnetic resonance (NMR) experiments. We propose that the N-terminal domain of hHCS recognizes the charged region of biotin acceptor protein, distinctly from the recognition by the catalytic domain.
人全羧化酶合成酶在催化结构域与大肠杆菌 BirA 等细菌生物素连接酶具有高度的序列同源性，但在 N 端的长度和序列上有所不同。尽管已经对 hHCS 的 N 端区域进行了多项研究，但该区域的作用仍不清楚。我们通过有限的蛋白水解确定了 hHCS 的 N 端结构域，并表明该结构域对酶活性具有关键作用。该结构域不仅与生物素接受蛋白相互作用，而且如核磁共振（NMR）实验所示，还与 hHCS 的催化结构域相互作用。我们提出，hHCS 的 N 端结构域识别生物素接受蛋白的带电区域，与催化结构域的识别明显不同。
