Streptococcus gordonii, an accessory pathogen and early colonizer of plaque, co‐aggregates with many oral species including Porphyromonas gingivalis. It causes α‐hemolysis on blood agar, a process mediated by H₂O₂ and thought to involve concomitant oxidation of hemoglobin (Hb). Porphyromonas gingivalis has a growth requirement for heme, which is acquired mainly from Hb. The paradigm for Hb heme acquisition involves the initial oxidation of oxyhemoglobin (oxyHb) to methemoglobin (metHb), followed by heme release and extraction through the actions of K‐gingipain protease and/or the HmuY hemophore‐like protein. The ability of S. gordonii to mediate Hb oxidation may potentially aid heme capture during co‐aggregation with P. gingivalis. Hemoglobin derived from zones of S. gordonii α‐hemolysis was found to be metHb. Generation of metHb from oxyHb by S. gordonii cells was inhibited by catalase, and correlated with levels of cellular H₂O₂ production. Generation of metHb by S. gordonii occurred through the higher Hb oxidation state of ferrylhemoglobin. Heme complexation by the P. gingivalis HmuY was employed as a measure of the ease of heme capture from metHb. HmuY was able to extract iron(III)protoporphyrin IX from metHb derived from zones of S. gordonii α‐hemolysis and from metHb generated by the action of S. gordonii cells on isolated oxyHb. The rate of HmuY‐Fe(III)heme complex formation from S. gordonii‐mediated metHb was greater than from an equivalent concentration of auto‐oxidized metHb. It is concluded that S. gordonii may potentially aid heme acquisition by P. gingivalis by facilitating metHb formation in the presence of oxyHb.

中文翻译：

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戈登链球菌来源的过氧化氢在牙龈卟啉单胞菌的血红素获取中的潜在作用。

戈登链球菌是一种病原体，是菌斑的早期定居者，它与包括牙龈卟啉单胞菌在内的许多口腔物种共同聚集。它会导致血琼脂上的α溶血，这是由H ₂ O ₂介导的过程，被认为与血红蛋白（Hb）的伴随氧化有关。牙龈卟啉单胞菌对血红素有生长需求，血红素主要来自血红蛋白。Hb血红素获得的范例涉及氧合血红蛋白（oxyHb）最初氧化为高铁血红蛋白（metHb），然后通过K-gingipain蛋白酶和/或HmuY血红素样蛋白的作用释放血红素。戈登酵母的能力介导Hb氧化可能与牙龈卟啉单胞菌共聚集期间可能有助于血红素捕获。发现来自戈登氏链球菌α-溶血区的血红蛋白达到metHb。过氧化氢酶抑制了戈登氏链球菌从oxyHb生成metHb ，并与细胞H ₂ O ₂产生水平相关。戈登氏链球菌通过高铁血红蛋白的Hb氧化态产生了metHb。牙龈卟啉单胞菌HmuY的血红素络合被用作从metHb捕获血红素的难易程度的一种度量。HmuY能够从来源于戈登氏链球菌（S. gordonii）的metHb中提取铁（III）原卟啉IXα溶血和metHb通过的作用而产生S.戈登细胞上分离oxyHb。戈登氏链霉菌介导的metHb形成HmuY-Fe（III）血红素复合物的速率大于同等浓度的自氧化metHb。结论是戈登链霉菌可能通过在oxyHb存在下促进metHb的形成来潜在地帮助牙龈卟啉单胞菌获得血红素。