Related Experiment Video

Updated: Aug 16, 2026

Immuno-fluorescence Assay of Leptospiral Surface-exposed Proteins
10:47

Immuno-fluorescence Assay of Leptospiral Surface-exposed Proteins

Published on: July 1, 2011

TP0453, a concealed outer membrane protein of Treponema pallidum, enhances membrane permeability

Karsten R O Hazlett1, David L Cox, Marc Decaffmeyer

  • 1Center for Microbial Pathogenesis, University of Connecticut Health Center, 263 Farmington Ave., Farmington, Connecticut 06030, USA. KHazlett@up.uchc.edu

Journal of Bacteriology
|September 15, 2005
PubMed

Insights

Treponema pallidum outer membrane protein TP0453 is a novel alpha-helical lipoprotein. It destabilizes membranes, potentially facilitating nutrient transport while evading antibodies.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Treponema pallidum, the agent of syphilis, has a unique outer membrane with few identified proteins.
  • Gram-negative bacteria typically utilize beta-barrel proteins for nutrient transport across their outer membranes.
  • T. pallidum lacks known porins and transporters, suggesting an alternative nutrient uptake mechanism.

Purpose of the Study:

  • To identify and characterize novel outer membrane proteins in Treponema pallidum.
  • To investigate the structure and function of TP0453, a potential nutrient transport protein.
  • To understand the unique outer membrane permeability of T. pallidum.

Main Methods:

  • Bioinformatic analysis of the T. pallidum genome.
  • Recombinant expression and purification of TP0453.
  • Lipoprotein characterization and structural analysis.
  • In vitro studies using artificial membranes to assess protein insertion and membrane permeability.

Main Results:

  • TP0453 is a lipoprotein with an amphipathic alpha-helical structure, unlike typical beta-barrel outer membrane proteins.
  • TP0453 does not appear to traverse the outer membrane to become surface-exposed.
  • Insertion of recombinant TP0453 into artificial membranes destabilized the bilayer and increased permeability.
  • The protein's structure suggests it may facilitate nutrient passage without antibody recognition.

Conclusions:

  • TP0453 represents a novel class of bacterial outer membrane protein.
  • This protein may be responsible for nutrient permeation across the T. pallidum outer membrane.
  • The unique structure of TP0453 could explain how T. pallidum acquires nutrients while evading host immune responses.

More Related Videos

Procedures for In Vitro Cultivation of Treponema pallidum, the Syphilis Spirochete09:45

Procedures for In Vitro Cultivation of Treponema pallidum, the Syphilis Spirochete

Published on: January 24, 2025

Imaging Plasma Membrane Deformations With pTIRFM12:28

Imaging Plasma Membrane Deformations With pTIRFM

Published on: April 2, 2014

Related Concept Videos

Structure of Porins01:21

Structure of Porins

Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a  motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel precursors...
Mechanism of Conjugation01:19

Mechanism of Conjugation

Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...
Protein Transport into the Inner Mitochondrial Membrane01:34

Protein Transport into the Inner Mitochondrial Membrane

Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Types of Membrane Protrusions01:28

Types of Membrane Protrusions

The protrusion of the cell surface is an initial step for several cellular processes, including cell migration, phagocytosis, and neurite outgrowth. These membrane protrusions are a result of cytoskeletal rearrangement. The most  widely observed cell protrusions include lamellipodia, pseudopodia, filopodia, microvilli, invadopodia, and podosomes. These protrusions can be of two types — static or dynamic.
The microvilli, an example of stable protrusions, are finger-like projections with a...
Protein Transport to the Outer Chloroplast Membrane01:11

Protein Transport to the Outer Chloroplast Membrane

Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.