>TIGR02037 degP_htrA_DO protease Do; InterPro: IPR011782 Proteolytic enzymes that exploit serine in their catalytic activity are ubiquitous, being found in viruses, bacteria and eukaryotes . They include a wide range of peptidase activity, including exopeptidase, endopeptidase, oligopeptidase and omega-peptidase activity. Over 20 families (denoted S1 - S66) of serine protease have been identified, these being grouped into clans on the basis of structural similarity and other functional evidence . Structures are known for members of the clans and the structures indicate that some appear to be totally unrelated, suggesting different evolutionary origins for the serine peptidases . Not withstanding their different evolutionary origins, there are similarities in the reaction mechanisms of several peptidases. Chymotrypsin, subtilisin and carboxypeptidase C have a catalytic triad of serine, aspartate and histidine in common: serine acts as a nucleophile, aspartate as an electrophile, and histidine as a base . The geometric orientations of the catalytic residues are similar between families, despite different protein folds . The linear arrangements of the catalytic residues commonly reflect clan relationships. For example the catalytic triad in the chymotrypsin clan (PA) is ordered HDS, but is ordered DHS in the subtilisin clan (SB) and SDH in the carboxypeptidase clan (SC) , . Peptidases are grouped into clans and families. Clans are groups of families for which there is evidence of common ancestry. Each clan is identified with two letters, the first representing the catalytic type of the families included in the clan (with the letter 'P' being used for a clan containing families of more than one of the catalytic types serine, threonine and cysteine). Some families cannot yet be assigned to clans, and when a formal assignment is required, such a family is described as belonging to clan A-, C-, M-, S-, T- or U-, according to the catalytic type. Some clans are divided into subclans because there is evidence of a very ancient divergence within the clan, for example MA(E), the gluzincins, and MA(M), the metzincins. Families are grouped by their catalytic type, the first character representing the catalytic type: A, aspartic; C, cysteine; G, glutamic acid; M, metallo; S, serine; T, threonine; and U, unknown. The serine, threonine and cysteine peptidases utilise the amino acid as a nucleophile and form an acyl intermediate - these peptidases can also readily act as transferases. In the case of aspartic, glutamic and metallopeptidases, the nucleophile is an activated water molecule. This family consists serine peptidases belonging to MEROPS peptidase family S1, subfamily S1C (protease Do, clan PA(S)). They are variously designated DegP, DegQ, heat shock protein HtrA, MucD and protease DO. The ortholog in Pseudomonas aeruginosa is designated MucD and is found in an operon that controls mucoid phenotype. This family also includes the DegQ (HhoA) paralog in Escherichia coli which can rescue a DegP mutant, but not the smaller DegS paralog, which cannot. Members of this family are located in the periplasm and have separable functions as both protease and chaperone. Members have a trypsin domain and two copies of a PDZ domain. This protein protects bacteria from thermal and other stresses and may be important for the survival of bacterial pathogens . The chaperone function is dominant at low temperatures, whereas the proteolytic activity is turned on at elevated temperatures .; GO: 0004252 serine-type endopeptidase activity, 0006508 proteolysis.

Probab=99.35  E-value=8.1e-13  Score=108.14  Aligned_cols=66  Identities=29%  Similarity=0.517  Sum_probs=59.7

Q ss_pred             CCCCCCCCCHHHHHHCCCCCEEEEECCCCCCCCHHHHHHCCC-CCCCCCEEEEEECCCCEEEECCCCC
Q ss_conf             000245675565300145662888878304540011111014-6788631699965873131011211
Q gi|254780773|r  121 VVSNVSPASPAAIAGVKKGDCIISLDGITVSAFEEVAPYVRE-NPLHEISLVLYREHVGVLHLKVMPR  187 (349)
Q Consensus       121 ~I~~V~~~spA~~AGL~~GD~Il~InG~~V~s~~dl~~~i~~-~~g~~v~i~v~R~~~~~~~~~v~p~  187 (349)
T Consensus       296 LV~~V~~gSPA~kAGlk~GDvI~~~nGk~i~~~~~L~~~i~~~~pG~~~~L~i~R~Gk~-~~~~V~l~  362 (484)
T TIGR02037       296 LVAQVLPGSPAEKAGLKAGDVILSVNGKKIKSFADLRRAIGTLKPGKKVTLTILRKGKE-KTITVTLG  362 (484)
T ss_pred             EEEEECCCCCHHCCCCCCCCEEEEECCEEECCHHHHHHHHHCCCCCCEEEEEEEECCEE-EEEEEEEE
T ss_conf             88854489701006753266899858864058799989874058987799999978868-88999981