Conformation of the Cell Division Regulator MinE: Evidence for Interactions between the Topological Specificity and Anti-MinCD Domains
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- 作者：Dennis Ramos ; Thierry Ducat ; Jenny Cheng ; Nelson F. Eng ; Jo-Anne R. Dillon ; and Natalie K. Goto
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：April 11, 2006
- 年：2006
- 卷：45
- 期：14
- 页码：4593 - 4601
- 全文大小：398K
- 年卷期：v.45,no.14(April 11, 2006)
- ISSN：1520-4995
文摘
Symmetric division of Gram-negative bacteria depends on the combined action of three proteinsthat ensure correct positioning of the cell division septum, namely, MinC, MinD, and MinE. To achievethis function, MinC and MinD form a membrane-bound complex that blocks cell division at all potentialsites. Opposing this inhibition is MinE, which interacts with MinD via its N-terminal anti-MinCD domainto site-specifically counter the action of the MinCD complex. The anti-MinCD domain has been proposedto bind MinD in a helical conformation; however, little is actually known about the structure of thisfunctionally critical region. To understand how MinE can perform its anti-MinCD function, we havetherefore investigated the conformation of the full-length MinE from Neisseria gonorrhoeae by solutionNMR. Although solubility considerations required the use of sample conditions that limit the observationof amide resonances to regions that are protected from solvent exchange, backbone chemical shifts fromboth N- and C-terminal domains could be assigned. In contrast to previous models, secondary chemicalshift analysis of these solvent-protected regions shows that parts of the N-terminal anti-MinCD domainare stably folded with many functionally important residues localizing to a 
le">-structure. In addition, thisN-terminal domain may be interacting with the C-terminal topological specificity domain, since mutationsmade in one domain led to NMR spectral changes in both domains. The nonfunctional MinE mutantL22D showed even larger evidence of structural perturbations in both domains, with significantdestabilization of the entire MinE structure. Overall, these results suggest that there is an intimate structuralassociation between the anti-MinCD and topological specificity domains, allowing the functional propertiesof the two domains to be modulated through this interaction.
le">-structure. In addition, thisN-terminal domain may be interacting with the C-terminal topological specificity domain, since mutationsmade in one domain led to NMR spectral changes in both domains. The nonfunctional MinE mutantL22D showed even larger evidence of structural perturbations in both domains, with significantdestabilization of the entire MinE structure. Overall, these results suggest that there is an intimate structuralassociation between the anti-MinCD and topological specificity domains, allowing the functional propertiesof the two domains to be modulated through this interaction.