Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/15406
Título: | A substrate translocation trajectory in a cytoplasm-facing topological model of the monocarboxylate/H+ symporter Jen1p |
Autor(es): | Silva, Isabel Soares Pessoa, Joana Sá Myrianthopoulos, Vassilios Mikros, Emmanuel Casal, Margarida Diallinas, George |
Palavras-chave: | Structure-function relationships Lactate permease Specificity Molecular simulations Substrate docking |
Data: | Ago-2011 |
Editora: | Wiley |
Revista: | Molecular Microbiology |
Resumo(s): | Previous mutational analysis of Jen1p, a Saccharomyces cerevisiae monocarboxylate/H+ symporter of the Major Facilitator Superfamily, has suggested that the consensus sequence 379NXX[S/T]HX[S/T]QD387 in transmembrane segment VII (TMS-VII) is part of the substrate translocation pathway. Here, we rationally design, analyse and show that several novel mutations in TMS-V and TMS-XI directly modify Jen1p function. Among the residues studied, F270 (TMS-V) and Q498 (TMS-XI) are critical specificity determinants for the distinction of mono- from di-carboxylates, and N501 (TMS-XI) is a critical residue for function. Using a model created on the basis of Jen1p similarity with the GlpT permease, we show that all polar residues critical for function within TMS-VII and TMS-XI (N379, H383, D387, Q498, N501) are perfectly aligned in an imaginary axis that lies parallel to a protein pore. This model and subsequent mutational analysis further reveal that an additional polar residue facing the pore, R188 (TMS-II), is irreplaceable for function. Our model also justifies the role of F270 and Q498 in substrate specificity. Finally, docking approaches reveal a ‘trajectory-like’ substrate displacement within the Jen1p pore, where R188 plays a major dynamic role mediating the orderly relocation of the substrate by subsequent H-bond interactions involving itself and residues H383, N501 and Q498. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/15406 |
DOI: | 10.1111/j.1365-2958.2011.07729.x |
ISSN: | 0950-382X |
Versão da editora: | http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2958.2011.07729.x/abstract |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | DBio - Artigos/Papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Jen1_Mol_Microbiol_REVISED with tables and figures.pdf | Documento principal | 1,08 MB | Adobe PDF | Ver/Abrir |