THE MOLECULAR STRUCTURE OF THE LIPOAMIDE DEHYDROGENASE DOMAIN (DLDH) OF A SURFACE ANTIGEN FROM NEISSERIA MENINGITIDIS Lucile Pernot1, Inés Li de la Sierra1,2 , Thierry Prangé1,3, Pedro Saludjian3, Marc Schiltz1, Roger Fourme1, Gabriel Padrón2 1LURE , Bâtiment 209, Université Paris-Sud, 91405-ORSAY CEDEX, France ;2CIGB, ave 31 entre 156 y 190, Cubanacan, La Habana, Cuba, 3Chimie Biomoléculaire (URA 1430 - CNRS), UFR-Biomédicale, 93012-BOBIGNY CEDEX, France
The domain involves the major antigenic determinant of P64k, a protein from the surface of the Nesseria Meningitidis bacteria has been localized in the X-ray structure at 2.9Å resolution. The P64k is a two domain protein comprizing a dihydrolipoamide dehydrogenase (DLDH) domain of c.a. 500 residues, and a smaller lipoic acid binding domain of 120 residues, connected together by a linker of twenty hydrophobic residues. The first domain involves a FAD prosthetic group and a NADH cofactor. The lipoic acid binding domain was easily cleaved and therefore was not observed in the X-ray structure. The structure of the DLDH domain was solved by a combination of molecular replacement (MR) and multiple isomorphous replacement (MIR) techniques using a TAMM (mercury) and a xenon derivatives.