cfp-10 cfp-10 cfp-10 within bacterial proteins (also known as esat-6-like protein esxb or secreted antigenic protein mtsa-10 or 10 kda culture filtrate antigen cfp-10) is a protein that is encoded by the esxb gene. 10 kda culture filtrate antigen cfp-10structure of the cfp10-esat6 complex from m. tuberculosis.identifiersorganismmycobacterium tuberculosissymbolesxbentrez886194pdb3favrefseq (prot)np_218391uniprotp0a566other datachromosomegenome: 4.35 - 4.35 mbsearch forstructuresswiss-modeldomainsinterpro cfp-10 is a 10 kda secreted antigen from mycobacterium tuberculosis. it forms a 1:1 heterodimeric complex with esat-6. both genes are expressed from the rd1 region of the bacterial genome and play a key role in the virulence of the infection. function 10-kda culture filtrate protein (cfp-10) is an antigen that contributes to the virulence mycobacterium tuberculosis. cfp-10 forms a tight 1:1 heterodimeric complex with 6kdaa early secreted antigen target (esat-6). in the mycobacterial cell, these two proteins are interdependent on each other for stability. the esat-6/cfp-10 complex is secreted by the esx-1 secretion system, also known as the rd1 region. mycobacterium tuberculosis uses this esx-1 secretion system to deliver virulence factors into host macrophage and monocyte white blood cells during infection. in mycobacterium tuberculosis, the core components of the whole esx-1 secretion system include rv3877, and two aaa atpases, including rv3870 and rv3871, a cytosolic protein. the esat-6/cfp-10 heterodimer complex is targeted for secretion by a c-terminal signal sequence on cfp-10 that is recognized by the cytosolic rv3871 protein. rv3871 then interacts with the cfp-10 c-terminal, and escorts the esat-6/cfp-10 complex to rv3870 and rv3877, a multi-transmembrane protein which makes up the pore that spans the cytosolic membrane of the virulent host cell. once esat-6/cfp-10 is next to the membrane of the virulent host cell, the cfp-10 c-terminal attaches and binds itself to the cells surface. the esat-6/cfp-10 complex’s secretion and attachment to the virulent host cell shows its contribution to the pathogenicity of mycobacterium tuberculosis. . structure the 10-kda culture filtrate protein (cfp-10) and 6kdaa early secreted antigen target (esat-6) complex is a 100 amino-acid sequence protein. esat-6/cfp-10 has a hydrophobic nature as well as a high content of α-helical structures. resonance structure analysis of the complex reveals two similar helix-turn-helix hairpin structures formed by the individual proteins, which lie anti-parallel to each other and forms a four-helix bundle. its long flexible arm projecting off the four-helix bundle, formed by the seven amino-acid c-terminal of cfp-10, is essential for binding and attaching to the surface of host white blood cells; such as macrophages and monocytes. if this c-terminus is cleaved off, the complex shows greatly reduced attachment ability.