Biological Projects

Dynamics of the YadA autotransporter in microcrystals and native membranes

YadA (Yersinia Adhesin A) is a member of the family of trimeric autotransporter adhesins, which are important pathogenicity factors that mediate adhesion to host cells and tissues in such diverse diseases as diarrhea, urinary tract infections, or airway infections.

The structure and dynamics of YadA are studied both in microcrystals and native membranes. Probing membrane protein dynamics in their natural lipid environment (the outer-membrane) is important to understand their actual biological activity.

Previous solid-state NMR studies in microcrystals provided information on flexibility and mobility of parts of the structure, which in combination with evolutionary conservation information allowed new insights into the autotransport mechanism of YadA. Currently, we use 15N and 13C’ spin-lattice relaxation rates (R1) and 15N, 13C’ spin-lattice relaxation rates in the rotating frame (R1r) to probe the dynamics of the backbone as well as peptide plane motions of YadA in two different environments, in microcrystals and in the outer-membrane. The present study aims to find out the similarities and differences in YadA protein motions when the protein is located in two different environments and also aims to identify the dynamics of residues which are involved in autotransporter mechanism. The experimental data was fit into two theoretical relaxation models such as simple model free (SMF) and extended model free (EMF) formalisms. The SMF model mainly reflects the information related to collective motions of the protein whereas EMF provides both slow and fast motions of the protein. 

 

References:

Shahid SA, Baridaux B, Franks WT, Krabben L, Habeck M, van Rossum BJ, Linke D (2012) Membrane-protein structure determination by solid-state NMR spectroscopy of microcrystals. Nat Methods 9, 1212-1217

Shahid SA, Markovic S, Linke D, van Rossum BJ (2012) Assignment and secondary structure of the YadA membrane protein by solid-state MAS NMR. Nature Scientific reports 2

The left panel shows the order parameters S2 obtained from 15N R1 and R1r relaxation parameters using the SMF model, for microcrystalline (top) and outer-membrane (bottom) YadA. The order parameters are color coded on the corresponding YadA structures (right).

(click on image to enlarge)

Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin e.V. (FMP)
Campus Berlin-Buch
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info(at)fmp-berlin.de

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