CpnT - Outer Membrane Channel Protein CpnT

β-Barrel Porins

These proteins form transmembrane pores that usually allow the energy independent passage of solutes across a membrane. The transmembrane portions of these proteins consist of β-strands which form a β-barrel. These porin-type proteins are found in the outer membranes of Gram-negative bacteria, mitochondria, plastids and possibly acid-fast Gram-positive bacteria.

95 subfamilies has been described by the Transporter Classification Database (TCDB).

CpnT Background Information


The outer membrane protein cpnT is expressed by the Mycobacterium tuberculosis. CpnT has a dual function in uptake of nutrients and induction of host cell death: After cleavage of the C-terminal region (TNT), the remaining protein (NTD) forms a pore assembled as Oligomer in the bacterial membrane.

Data Sheet:


UniProt: O05442

Topology and Function:
cpnT (Mycobacterium tuberculosis) has a dual function in uptake of nutrients and induction of host cell death. The N-terminal domain (NTD) forms an outer membrane channel and is used for uptake of nutrients across the outer membrane. The cleaved and secreted C-terminal toxic domain (TNT) acts as a glycohydrolase, which hydrolyzes the essential cellular coenzyme NAD+ in the cytosol of infected macrophages, leading to necrotic host cell death. TNT is Secreted into the cytosol of infected macrophages while the bacteria are still confined to the phagosome. Both functions are required for survival, replication and cytotoxicity of M.tuberculosis in macrophages.


icon pap   &   Icon Orbit Mini   Bilayer recordings on Port-a-Patch and Orbit mini 

Reviews and Links


2014 - An outer membrane channel protein of Mycobacterium tuberculosis with exotoxin activity

icon pap  Port-a-Patch and   icon vpp   Vesicle Prep Pro publication in Proceedings of the National Academy of Sciences of the United States of America (2014)

Danilchanka A., Sun J., Pavlenok M., Maueröder C., Speer A., Siroy A., Marrero J., Trujillo C., Mayhew D.L., Doornbos K.S., Muñoz 'L.E., HerrmannM., EhrtS., Berens C., Niederweisa M.


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