Biosynthesis of peptidoglycan in Gaffkya homari: processing of nascent glycan by reactivated membranes.
Biosynthesis of peptidoglycan in Gaffkya homari: processing of nascent glycan by reactivated membranes.
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Gaffkya homari 中肽聚糖的生物合成：通过重新激活的膜处理新生聚糖。
DOI：
10.1128/jb.157.2.398-404.1984
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发表时间：
1984
影响因子：
3.2
通讯作者：
Neuhaus,FC
中科院分区：
文献类型：
--
作者：
Bardin,C;Sinha,RK;Kalomiris,E;Neuhaus,FC
利用冻融复活的Gaffkya homari膜，研究了十二烷基硫酸钠(SDS)-不溶肽聚糖(PG)和十二烷基硫酸钠-可溶性PG组装过程中的加工事件。重新激活用于合成这些聚合物的膜的能力为监测那些不受壁联PG影响的事件提供了机会。在棉铃虫中，形成交联链的过程需要DD-羧基肽酶、LD-羧基肽酶和NE-(DALA)-赖氨酸转肽酶的选择性作用。用酰胺化双糖多肽二聚体和非酰胺化双糖多肽二聚体的量来衡量交联剂形成的时间进程，与合成不溶于十二烷基硫酸钠的PG的时间进程没有相关性。不溶于十二烷基硫酸钠的葡聚糖是不溶于十二烷基硫酸钠的葡聚糖的前体，在没有青霉素G的情况下合成时会发生显著的交联。在青霉素G存在下，合成了非交联型十二烷基硫酸钠可溶PG。该PG还用于脱除β-内酰胺后合成交联型不溶于十二烷基硫酸钠的PG。该方案提供了一种将PG的合成和延伸阶段与加工过程中的阶段分开的方法。不同组分的交联度在可溶于十二烷基硫酸钠的葡聚糖中为0-19%，在不溶于十二烷基硫酸钠的葡聚糖中为2-24%。因此，结果表明，十二烷基硫酸钠的不溶性与交联度没有直接的关系。相反，他们认为，额外的特征可能有助于PG在十二烷基硫酸钠中的不溶。
Membranes from Gaffkya homari reactivated by freezing and thawing were used to study the processing events involved in the assembly of both sodium dodecyl sulfate (SDS)-insoluble peptidoglycan (PG) and SDS-soluble PG. The ability to reactivate membranes for the synthesis of these polymers provided an opportunity to monitor those events that are not influenced by wall-linked PG. In G. homari, processing for the formation of cross-links requires the selective actions of DD-carboxypeptidase, LD-carboxypeptidase, and NE-(DAla)-Lys transpeptidase. Time courses of cross-link formation, as measured by the amounts of amidated bisdisaccharide peptide dimer and nonamidated bisdisaccharide peptide dimer, showed a lack of correlation with those for the synthesis of SDS-insoluble PG. SDS-soluble PG, which is significantly cross-linked when synthesized in the absence of penicillin G, was a precursor of the SDS-insoluble PG. In the presence of penicillin G, un-cross-linked SDS-soluble PG was synthesized. This PG was also utilized and processed for the synthesis of cross-linked SDS-insoluble PG after removal of the beta-lactam. This protocol provided a method for separating stages in the synthesis and elongation of PG from those involved in processing. Cross-linkage in the various PG fractions ranged from 0 to 19% in SDS-soluble PG and from 2 to 24% in SDS-insoluble PG. Thus, the results indicated that there is no direct correlation between SDS insolubility and the degree of cross-linkage. Instead, they suggested that additional features may contribute to the insolubility of PG in SDS.