>TIGR02552 LcrH_SycD type III secretion low calcium response chaperone LcrH/SycD; InterPro: IPR005415 The type III secretion system of Gram-negative bacteria is used to transport virulence factors from the pathogen directly into the host cell and is only triggered when the bacterium comes into close contact with the host. Effector proteins secreted by the type III system do not possess a secretion signal, and are considered unique because of this. Yersinia spp. secrete effector proteins called YopB and YopD that facilitate the spread of other translocated proteins through the type III needle and the host cell cytoplasm . Both are believed to act as pore translocases, forming apertures in the host cell membrane and allowing the bacterium easy access to its cytoplasm. YopD also acts as a negative regulator of the Yersinia low-calcium response, and in turn is controlled by a chaperone, SycD . This protein also regulates YopB secretion. SycD is located on the Yop pathogenicity island of Yersinia spp., and is speculated to prevent a premature interaction between YopB, YopD and the calcium-response LcrV protein . It has been speculated that a type III secretion mechanism also exists in Chlamydial species. With the sequencing of the Chlamydia trachomatis genome, several proteins similar to characterised type III proteins have emerged, including a SycD homologue . The Pseudomonas aeruginosa gene PcrH is also similar to the Yersinia chaperone, suggesting a comparable function. Proteins in this entry are found in type III secretion operons. LcrH, from Yersinia is believed to have a regulatory function in the low-calcium response of the secretion system ,. The same protein is also known as SycD (SYC = Specific Yop Chaperone) for its chaperone role . In Pseudomonas, where the homolog is known as PcrH, the chaperone role has been demonstrated and the regulatory role appears to be absent . ScyD/LcrH contains three central tetratricopeptide-like repeats that are predicted to fold into an all-alpha-helical array .; GO: 0006950 response to stress.

Probab=97.48  E-value=0.006  Score=41.01  Aligned_cols=106  Identities=15%  Similarity=0.051  Sum_probs=87.1

Q ss_pred             CCHHHHHH-HHHHHHHHHHCCHHHHHHHHHHHHCCCCHHHHHHHHHHHHHCCCCHHHHHHHHHHHHHHCCCCHHHHHHHH
Q ss_conf             61589999-98753222210001689999997268850579998654552158869999999988842126989999999
Q gi|254781033|r  117 HNEYLVYL-LEVQIALAERQYNIAHEKLEMMLQIPATREFAVYSLYFESCRIGDLNSAQRYATKALDISPDAPWVTEAVV  195 (492)
Q Consensus       117 ~~~~L~~L-l~A~aA~~~gd~~~A~~~~~~~~~~~~~~~~~~~gL~~~al~~gd~~~A~~~~~~a~~~~P~~~~a~~~L~  195 (492)
T Consensus        14 ~~~~L~~~Y~~AY~~y~~G~Y~~A~~~F~~L~~~~~~~~~Y~~gLa~c~q~~~~Y~~A~~~Y~~a~~l~~~~P~p~~~~a   93 (137)
T TIGR02552        14 DSEQLEAIYALAYNLYQQGRYDEALKLFQLLAAYDPWNADYWLGLAACCQMLKEYEEAIDAYALAAALDPDDPRPYYHAA   93 (137)
T ss_pred             CHHHHHHHHHHHHHHHHCCCHHHHHHHHHHHHHHCCHHHHHHHHHHHHHHHHHCHHHHHHHHHHHHHCCCCCCCCHHHHH
T ss_conf             99899999999999985366799999999999974303689999999999861678999999999752768695126998


Q ss_pred             HHHHHCCCCHHHHHHHHHHHHCCC-CHH
Q ss_conf             999952574569999999995023-103
Q gi|254781033|r  196 QQYVLAKEWSRAITFLNQKKKNAK-EWN  222 (492)
Q Consensus       196 ~l~~~~gdw~~A~~~l~~~~~~~~-~~~  222 (492)
T Consensus        94 ~C~l~~g~~~~A~~aL~~a~~~~~~~~~  121 (137)
T TIGR02552        94 ECYLALGEPESALKALDLAIEIAGGENP  121 (137)
T ss_pred             HHHHHHCCHHHHHHHHHHHHHHHCCCCC
T ss_conf             9998728978999999999998488996