The lipid-containing bacteriophage PR4. Effects of altered lipid composition on the virion.
The lipid-containing bacteriophage PR4. Effects of altered lipid composition on the virion.
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含脂噬菌体PR4。
DOI：
10.1016/s0022-2836(83)80245-9
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发表时间：
1983
影响因子：
5.6
通讯作者：
CronanJr,JE
中科院分区：
文献类型：
--
作者：
Muller,ED;CronanJr,JE
噬菌体PR4生长在多种脂肪酸和磷脂代谢缺陷的埃希氏菌共变物上。通过改变宿主膜磷脂的组成来改变噬菌体脂质的组成。磷脂极性部分和酰基部分的组成都发生了变化。利用具有不饱和脂肪酸生物合成温度敏感缺陷的宿主突变体，噬菌体磷脂中饱和脂肪酸的比例从总脂肪酸的44%逐渐增加到总脂肪酸的55%、61%和69%。当噬菌体在2°C至30°C（低于噬菌体生长的温度）的温度下孵育时，饱和脂肪酸的增加导致感染性明显丧失。噬菌体磷脂中饱和脂肪酸的含量越高，噬菌体灭活的温度越高。我们的研究结果强烈表明，噬菌体膜经历了脂质相变，这可以破坏和灭活病毒粒子。宿主突变体的磷脂酰乙醇胺和/或心磷脂合成缺陷也改变了PR4的磷脂组成。在野生型宿主菌株上生长的噬菌体PR4含有56%的磷脂酰乙醇胺、37%的磷脂酰甘油、4.6%的心磷脂，未检测到磷脂酰丝氨酸。然而，为了响应宿主的变化，PR4制剂的磷脂成分从28%到60%不等，磷脂酰乙醇胺含量从22%到39%不等，心磷脂含量从1%到15%不等，磷脂酰丝氨酸含量高达35%。这些磷脂组成的变化不影响噬菌体的感染性。此外，这些操作并没有改变噬菌体中相对于宿主的磷脂酰甘油水平的增加。结果表明，噬菌体膜磷脂的净电荷与病毒磷脂的选择和功能无关。我们也提出证据表明，噬菌体和宿主膜在感染过程中不融合。
Phage PR4 was grown on a variety ofEscherichia colimutants defective in fatty acid and phospholipid metabolism. The composition of the phage lipids was modified by changing the composition of the host membrane phospholipids. The compositions of both the polar and the acyl moieties of the phospholipids were altered.The proportion of saturated fatty acids in the phage phospholipids was increased in increments from 44% of the total fatty acids to 55%, 61% and 69% of the total fatty acids using a host mutant with a temperature-sensitive defect in unsaturated fatty acid biosynthesis. The increase in saturated fatty acids led to a pronounced loss of infectivity when the phage were incubated at temperatures between 2°C and 30°C (temperatures below those at which the phage were grown). The greater the level of saturated fatty acids in the phage phospholipids, the higher the temperature below which the phage were inactivated. Our results strongly suggest that the phage membrane undergoes a lipid phase transition, which can disrupt and inactivate the virion.The phospholipid composition of PR4 was also altered by using host mutants defective in phosphatidylethanolamine and/or cardiolipin synthesis. Phage PR4 grown on wild-type host strains contains 56% phosphatidylethanolamine, 37% phosphatidylglycerol, 4·6% cardiolipin and no detectable phosphatidylserine. However, in response to changes in this host, PR4 preparations were obtained with phospholipid compositions varying from 28% to 60% in phosphatidylethanolamine, from 22% to 39% in phosphatidylglycerol, from 1% to 15% in cardiolipin and containing as much as 35% phosphatidylserine. These changes in phospholipid composition did not affect the infectivity of the phage. Moreover, the increased level of phosphatidylglycerol in the phage relative to the host was not altered by these manipulations. It is concluded that the net charge of the phage membrane phospholipids is not involved in the selection or function of the viral phospholipids.We also present evidence suggesting that the phage and host membranes do not fuse during the course of infection.