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The relationship between hetero‐oligomer formation and function of the topological specificity domain of the Escherichia coli MinE protein
Author(s) -
Zhang Yan,
Rowland Susan,
King Glenn,
Braswell Emory,
Rothfield Lawrence
Publication year - 1998
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1998.01059.x
Subject(s) - oligomer , escherichia coli , cytoplasm , biology , monomer , ultracentrifuge , function (biology) , fragment (logic) , biophysics , topology (electrical circuits) , biochemistry , microbiology and biotechnology , chemistry , gene , polymer , polymer chemistry , algorithm , mathematics , organic chemistry , combinatorics , computer science
MinE is an oligomeric protein that, in conjunction with other Min proteins, is required for the proper placement of the cell division site of Escherichia coli . We have examined the self‐association properties of MinE by analytical ultracentrifugation and by studies of hetero‐oligomer formation in non‐denaturing polyacrylamide gels. The self‐association properties of purified MinE predict that cytoplasmic MinE is likely to exist as a mixture of monomers and dimers. Consistent with this prediction, the C‐terminal MinE 22–88 fragment forms hetero‐oligomers with MinE + when the proteins are co‐expressed. In contrast, the MinE 36–88 fragment does not form MinE + /MinE 36–88 hetero‐oligomers, although MinE 36–88 affects the topological specificity of septum placement as shown by its ability to induce minicell formation when co‐expressed with MinE + in wild‐type cells. Therefore, hetero‐oligomer formation is not necessary for the induction of minicelling by expression of MinE 36–88 in wild‐type cells. The interference with normal septal placement is ascribed to competition between MinE 36–88 and the corresponding domain in the complete MinE protein for a component required for the topological specificity of septal placement.