Lipopolysaccharide structure determines ionic and hydrophobic binding of a cationic antimicrobial neutrophil granule protein.
Lipopolysaccharide structure determines ionic and hydrophobic binding of a cationic antimicrobial neutrophil granule protein.
复制标题
脂多糖结构决定阳离子抗菌中性粒细胞颗粒蛋白的离子和疏水结合。
DOI：
10.1128/iai.56.6.1589-1592.1988
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发表时间：
1988
影响因子：
3.1
通讯作者：
Spitznagel,JK
中科院分区：
文献类型：
--
作者：
Farley,MM;Shafer,WM;Spitznagel,JK
57，000-道尔顿阳离子抗微生物中性粒细胞颗粒蛋白（CAP 57）的杀菌活性和结合由细菌上O-抗原多糖链的存在和脂多糖的脂质A区、内核区或两个区中带负电荷基团的可用性来确定。在脂质A结构和电荷（pmrA）中具有明确改变的多粘菌素B（PMB）抗性突变体也对CAP 57更具抗性。我们使用生物活性的放射性碘标记的CAP 57研究的特性和动力学的结合敏感的Rb脂多糖化学型，鼠伤寒沙门氏菌SH 9178，和相对耐药的pmrA突变株SH 7426。结合发生迅速，并且是特异性和可饱和的。因为CAP 57似乎以与PMB类似的方式结合，所以进行竞争结合研究。过量的PMB确实与CAP 57竞争结合SH 9178。九肽是PMB的聚阳离子衍生物，失去了其疏水部分，与PMB相比，与CAP 57竞争结合的能力明显降低。这证明了疏水结合在CAP 57与微生物表面相互作用中的重要性。因此，我们已经表明，CAP 57与SH 9178的结合是特异性的、可饱和的，并且与PMB的结合相似。CAP 57的疏水性和离子性似乎是结合所必需的。
Bactericidal activity and binding of a 57,000-dalton cationic antimicrobial neutrophil granule protein (CAP57) are determined by the presence on bacteria of O-antigen polysaccharide chains and the availability of negatively charged groups in the lipid A region, the inner core region, or both regions of lipopolysaccharide. Polymyxin B (PMB)-resistant mutants with well-defined alterations in lipid A structure and charge (pmrA) are also more resistant to CAP57. We used biologically active radioiodinated CAP57 to study the characteristics and kinetics of binding to a sensitive Rb lipopolysaccharide chemotype, Salmonella typhimurium SH9178, and the relatively resistant pmrA mutant strain SH7426. Binding occurred rapidly and was specific and saturable. Because CAP57 appears to be bound in a manner similar to that of PMB, competition binding studies were performed. Excess PMB did compete with CAP57 for binding to SH9178. Nonapeptide, a polycationic derivative of PMB that has lost its hydrophobic portions, demonstrated a marked decrease in ability to compete for binding with CAP57 compared with PMB. This demonstrated the importance of hydrophobic binding in the interaction of CAP57 with the microbial surface. Thus, we have shown that binding of CAP57 to SH9178 is specific, saturable, and similar to binding of PMB. Both hydrophobic and ionic properties of CAP57 appear to be necessary for binding.