Structural evidence that the 32-kilodalton lipoprotein (Tp32) of Treponema pallidum is an L-methionine-binding protein

Ranjit K. Deka, Lori Neil, Kayla E. Hagman, Mischa Machius, Diana R. Tomchick, Chad A. Brautigam, Michael V. Norgard

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31 Scopus citations


A structure-to-function approach was undertaken to gain insights into the potential function of the 32-kDa membrane lipoprotein (Tp32) of Treponema, pallidum, the syphilis bacterium. The crystal structure of rTp32 (determined at a resolution of 1.85 A) shows that the organization of rTp32 is similar to other periplasmic ligand-binding proteins (PLBPs), in that it consists of two α/β domains, linked by two crossovers, with a binding pocket between them. In the pocket, a molecule of L-methionine was detected in the electron density map. Residues from both domains interact with the ligand. One of the crossover regions is comprised of a 310-helix, a feature not typical in other ligand-binding proteins. Sequence comparison shows strong similarity to other hypothetical methionine-bmding proteins. Together, the data support the notion that rTp32 is a component of a periplasmic methionine uptake transporter system in T. pallidum.

Original languageEnglish (US)
Pages (from-to)55644-55650
Number of pages7
JournalJournal of Biological Chemistry
Issue number53
StatePublished - Dec 31 2004


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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