Papathanasopoulos Maria A, Dykes Gary A, Revol-Junelles Anne-Marie, Delfour Antoine, von Holy Alexander, Hastings John W
Department of Genetics, University of Natal, Pietermaritzburg, Private Bag X01, Scottsville, 3209, South Africa.
Department of Microbiology, University of the Witwatersrand, Private Bag 3, WITS, 2050, South Africa.
Microbiology (Reading). 1998 May;144 ( Pt 5):1343-1348. doi: 10.1099/00221287-144-5-1343.
Amino acid sequences of two of the three bacteriocins from Leuconostoc mesenteroides TA33a were determined and their sequence-structure relationships investigated. Leucocin B-TA33a consists of 31 amino acid residues, with a molecular mass of 3466 Da. Leucocin B-TA33a does not belong to the pediocin family of bacteriocins, but shares 62% homology with mesenterocin 52B. A partial sequence of 36 amino acids of leucocin C-TA33a (4598 Da) was determined. Leucocin C-TA33a belongs to the class II bacteriocins having the consensus YGNGV motif. The third bacteriocin, leucocin A-TA33a, is identical to leucocin A-UAL 187. Circular dichroism spectra of the leucocins in aqueous solution and micellar SDS indicated that they undergo a structural transition when in a membrane-mimicking environment. Theoretical predictions from circular dichroism data suggest that leucocins A-, B- and C-TA33a adopt a beta-structure (48%) in membrane-mimicking environments. Sequence alignments and secondary structure predictions for the N-terminus of leucocins A- and C-TA33a predicted that Cys-9 and Cys-14 are connected by a disulfide bridge and form two beta-strands.
测定了肠系膜明串珠菌TA33a的三种细菌素中两种的氨基酸序列，并研究了它们的序列-结构关系。Leucocin B-TA33a由31个氨基酸残基组成，分子量为3466 Da。Leucocin B-TA33a不属于细菌素的片球菌素家族，但与肠膜菌素52B有62%的同源性。测定了Leucocin C-TA33a（4598 Da）的36个氨基酸的部分序列。Leucocin C-TA33a属于具有共有基序YGNGV的II类细菌素。第三种细菌素Leucocin A-TA33a与Leucocin A-UAL 187相同。Leucocin在水溶液和胶束SDS中的圆二色光谱表明，它们在模拟膜的环境中会发生结构转变。根据圆二色性数据的理论预测表明，Leucocin A-、B-和C-TA33a在模拟膜的环境中采用β-结构（48%）。Leucocin A-和C-TA33a N端的序列比对和二级结构预测表明，Cys-9和Cys-14通过二硫键连接，形成两条β-链。
