The penicillin sensory transducer, BlaR, involved in the inducibility of beta-lactamase synthesis in Bacillus licheniformis is embedded in the plasma membrane via a four-alpha-helix bundle
The penicillin sensory transducer, BlaR, involved in the inducibility of beta-lactamase synthesis in Bacillus licheniformis is embedded in the plasma membrane via a four-alpha-helix bundle
复制标题
DOI：
10.1046/j.1365-2958.1997.2761642.x
复制
发表时间：
1997-03-01
影响因子：
3.6
通讯作者：
Ghuysen, JM
中科院分区：
文献类型：
--
作者：
Hardt, K;Joris, B;Ghuysen, JM
预测研究、构象分析和膜拓扑作图得出结论，在地衣芽孢杆菌中参与诱导β-内酰胺酶合成的青霉素传感器BlaR通过形成四-α-螺旋束的四个跨膜区段TM 1-TM 4嵌入质膜双层中。胞外262个氨基酸残基的多肽S340-R601，融合在TM 4的羧基末端，具有青霉噻唑酰丝氨酸转移酶的氨基酸序列特征。它可能起青霉素传感器的作用。作为一个独立的实体，该多肽表现为高亲和力的青霉素结合蛋白。作为全长BlaR的组分，它采取不同的构象，这可能是因为与连接TM 2和TM 3的细胞外63个氨基酸残基的P53-S115环相互作用，接受青霉素-诱导的信号需要传感器的精确构象，但它不涉及基序STYK的丝氨酸残基S402的青霉酰化，四-α-螺旋束通过质膜的信号传递可以以与天冬氨酸受体Tar相当的方式进行。细胞溶质中连接TM 3和TM 4的细胞内189-氨基酸残基Y134-K322环的信号发射可以通过假定的金属肽酶的激活进行。
Prediction studies, conformational analyses and membrane-topology mapping lead to the conclusion that the penicillin sensory transducer, BlaR, involved in the inducibility of beta-lactamase synthesis in Bacillus licheniformis, is embedded in the plasma membrane bilayer via four transmembrane segments TM1-TM4 that form a four-alpha-helix bundle, The extracellular 262-amino-acid-residue polypeptide, S340-R601, that is fused at the carboxy end of TM4, possesses the amino acid sequence signature of a penicilloyl serine transferase. It probably functions as penicillin sensor. As an independent entity, this polypeptide behaves as a high-affinity penicillin-binding protein, As a component of the full-size BlaR, it adopts a different conformation presumably because of interactions with the extracellular 63-amino-acid-residue P53-S115 loop that connects TM2 and TM3, Reception of the penicillin-induced signal requires a precise conformation of the sensor but it does not involve penicilloylation of the serine residue S402 of motif STYK, Signal transmission through the plasma membrane by the four-alpha-helix bundle may proceed in a way comparable to that of the aspartate receptor, Tar, Signal emission in the cytosol by the intracellular 189-amino-acid-residue Y134-K322 loop that connects TM3 and TM4, may proceed via the activation of a putative metallopeptidase.