2014年8月7日 訊 /生物谷BIOON/ --近日，來自瑞典隆德大學的科學家通過研究首次揭示了，氣管中的細菌如何互相協助來補充其生長所需的鐵，進而增加細菌生存的機會，給人類的健康帶來隱患，相關研究刊登於國際雜誌International Journal of Medical Microbiology上。
流感嗜血桿菌是一種生活在呼吸道的細菌，其會引發耳朵感染，並且使得患慢性梗阻性肺部疾病(COPD)的患者病情加重，有些時候流感嗜血桿菌可導致腦膜炎和敗血病；研究者Kristian Riesbeck表示，在一種特殊蛋白的幫助下，流感嗜血桿菌可以互相幫助供給細菌彼此所需的鐵離子，從而使得細菌在宿主中生存下去。
機體中活的有機體需要鐵離子來生存，鐵離子可以通過血液中循環的一種蛋白質來獲取，早期研究顯示，細菌細胞的表層可以被設計修飾用來吸附所需類型的蛋白質。宿主機體中的鐵一般會大量累積，而細菌則會想盡一切辦法去獲取鐵。
流感嗜血桿菌可以將鐵離子結合到特殊蛋白E上，研究者表示，此前研究發現流感嗜血桿菌可以將鐵離子同化後留作自己用，但是本文研究中研究者卻發現，細菌可以通過另外一種途徑來利用鐵離子，裝載鐵離子的細菌可以將其部分裝載物（鐵離子）轉移到其它的流感嗜血桿菌中供其生長利用。
研究者表示，蛋白E通常可以影響COPD患者的病情，其也是開發治療感染的疫苗候選者，本文研究對於後期開發新型靶向疫苗以及治療細菌性感染疾病的療法提供了很好的參考依據和線索。目前研究人員計劃檢測其它細菌，尤其是肺炎鏈球菌是否可以利用流感嗜血桿菌的蛋白E來攝入鐵離子引發共感染，肺炎鏈球菌和流感嗜血桿菌是引發耳部感染、鼻竇炎和肺炎的常見細菌。（生物谷Bioon.com）
Haemophilus influenzae stores and distributes hemin by using Protein E
Tamim Al Jubaira, Birendra Singha, Christophe Fleurya, Anna M. Blomb, Matthias Mörgelinc, Marjolein M. Thunnissend, Kristian Riesbecka
The human pathogen Haemophilus influenzae causes mainly respiratory tract infections such as acute otitis media in children and exacerbations in patients with chronic obstructive pulmonary disease. We recently revealed the crystal structure of H. influenzeae protein E (PE), a multifunctional adhesin that is involved in direct interactions with lung epithelial cells and host proteins. Based upon the PE structure we here suggest a hypothetical binding pocket that is compatible in size with a hemin molecule. An H. influenzae mutant devoid of PE bound significantly less hemin in comparison to the PE-expressing wild type counterpart. In addition, E. coli expressing PE at the surface resulted in a hemin-binding phenotype. An interaction between hemin and recombinant soluble PE was also demonstrated by native-PAGE and UV-visible spectrophotometry. Surface plasmon resonance revealed an affinity (Kd) of 1.6 × 10−6 M for the hemin-PE interaction. Importantly, hemin that was bound to PE at the H. influenzae surface, was donated to co-cultured luciferase-expressing H. influenzae that were starved of hemin. When hemin is bound to PE it thus may serve as a storage pool for H. influenzae. To our knowledge this is the first report showing that H. influenzae can share hemin via a surface-located outer membrane protein.