Purification and spectroscopic characterization of Ctb, a group III truncated hemoglobin implicated in oxygen metabolism in the food-borne pathogen Campylobacter jejuni.
Purification and spectroscopic characterization of Ctb, a group III truncated hemoglobin implicated in oxygen metabolism in the food-borne pathogen Campylobacter jejuni.
复制标题
Ctb 的纯化和光谱表征，Ctb 是一种 III 族截短的血红蛋白，与食源性病原体空肠弯曲杆菌的氧代谢有关。
DOI：
10.1021/bi052247k
复制
发表时间：
2006
期刊：
影响因子：
2.9
通讯作者：
Poole,RobertK
中科院分区：
文献类型：
--
作者：
Wainwright,LauraM;Wang,Yinghua;Park,SimonF;Yeh,Syun-Ru;Poole,RobertK
Campylobacter jejuniis a food-borne bacterial pathogen that possesses two distinct hemoglobins, encoded by thectbandcgbgenes. The former codes for a truncated hemoglobin (Ctb) in group III, an assemblage of uncharacterized globins in diverse clinically and technologically significant bacteria. Here, we show that Ctb purifies as a monomeric, predominantly oxygenated species. Optical spectra of ferric, ferrous, O2- and CO-bound forms resemble those of other hemoglobins. However, resonance Raman analysis shows Ctb to have an atypical νFe-COstretching mode at 514 cm-1, compared to those of the other truncated hemoglobins that have been characterized so far. This implies unique roles in ligand stabilization for TyrB10, HisE7, and TrpG8, residues highly conserved within group III truncated hemoglobins. BecauseC. jejuniis a microaerophile, and actbmutant exhibits O2-dependent growth defects, one of the hypothesized roles of Ctb is in the detoxification, sequestration, or transfer of O2. The midpoint potential (Eh) of Ctb was found to be −33 mV, but no evidence was obtained in vitro to support the hypothesis that Ctb is reducible by NADH or NADPH. This truncated hemoglobin may function in the facilitation of O2transfer to one of the terminal oxidases ofC. jejunior, instead, facilitate O2transfer to Cgb for NO detoxification.
