This RNA binding domain is found at the amino terminus of transcriptional antitermination proteins such as BglG, SacY and LicT. These proteins control the expression of sugar metabolising operons in Gram-positive and Gram-negative bacteria. This domain has been called the CAT (Co-AntiTerminator) domain. It binds as a dimer []to short Ribonucleotidic Anti-Terminator (RAT) hairpin, each monomer interacting symmetrically with both strands of the RAT hairpin []. In the full-length protein, CAT is followed by two phosphorylatable PTS regulation domains that modulate the RNA binding activity of CAT. Upon activation, the dimeric proteins bind to RAT targets in the nascent mRNA, thereby preventing abortive dissociation of the RNA polymerase from the DNA template [].
This RNA binding domain is found at the N terminus of transcriptional antitermination proteins such as BglG, SacY and LicT. These proteins control the expression of sugar metabolising operons in Gram-positive and Gram-negative bacteria. This domain has been called the CAT (Co-AntiTerminator) domain. It binds as a dimer []to short Ribonucleotidic Anti-Terminator (RAT) hairpin, each monomer interacting symmetrically with both strands of the RAT hairpin []. In the full-length protein, CAT is followed by two phosphorylatable PTS regulation domains that modulate the RNA binding activity of CAT. Upon activation, the dimeric proteins bind to RAT targets in the nascent mRNA, thereby preventing abortive dissociation of the RNA polymerase from the DNA template [].
This entry represents the human Cat eye syndrome critical region protein 6 (also known as transmembrane protein 121B) and its homologues [, ]. Cat Eye Syndrome (CES) is characterised clinically by the combination of coloboma of the iris and anal atresia with fistula. CES is a rare condition caused by the duplication of a 2 Mb region of human 22q11.2 resulting in four copies of the region rather than the usual two copies [].
CECR5 (cat eye syndrome critical region protein 5 also known as haloacid dehalogenase-like hydrolase domain-containing 5) gene is a candidate gene for the Cat Eye Syndrome (CES), a developmental disorder associated with the duplication of a 2 Mb region of 22q11.2 []. Its function isnot clear.
This family includes Cat eye syndrome critical region protein 6 (also known as TMEM121B), a protein which has been identified in a screen for candidate genes for the developmental disorder Cat Eye Syndrome (CES) []. It also includes the TMEM121 transmembrane proteins. The function of this family is unknown.
This domain is found to the N terminus of the Adenosine/AMP deaminase domain () in metazoan proteins such as the Cat eye syndrome critical region protein 1 and its homologues.
Chloramphenicol acetyltransferase (CAT) () []catalyzes the acetyl-CoA dependent acetylation of chloramphenicol (Cm), an antibiotic which inhibits prokaryotic peptidyltransferase activity. Acetylation of Cm by CAT inactivates the antibiotic. The pattern signature for this entry contains the histidine residue, located in the C-terminal section of the enzyme, that plays a central role in its catalytic mechanism.There is a second family of CAT [], evolutionary unrelated to the main family described above. These CAT belong to the bacterial hexapeptide-repeat containing-transferases family (see ).The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilised by a number of hydrogen bonds, some of which result in the extension of a β-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilisation is provided by an unusual interaction with a main-chain carbonyl oxygen [].This signature pattern covers the region surrounding an active site histidine residue located in the C-terminal section of the enzyme; this residue plays a central role in its catalytic mechanism.
The ModE-Mo complex acts as a repressor of the modABC operon, which is involved in the transport of molybdate. Upon binding molybdate, the conformation of the protein changes, promoting dimerization of ModE-Mo. The protein dimer is then competent to bind a DNA region, upstream of the modABC operon, which contains an 8-base inverted repeat 5'-TAACGTTA-3' flanked by two CAT boxes. ModE also interacts with tungstate [].
Chromatin remodeling regulator CECR2 is part of the CERF (CECR2-containing-remodeling factor) complex, which is a chromatin remodelling complex that plays important roles in embryogenesis and neurulation [, , , ]. It may also contribute to spermatogenesis and form complexes with SNF2H in the testis [].CECR2 gene is a candidate gene for the Cat Eye Syndrome (CES), a developmental disorder associated with the duplication of a 2 Mb region of 22q11.2 [].
Toxoplasma gondii is an obligate intracellular apicomplexan protozoan parasite, with a complex lifestyle involving varied hosts. It has two phases of growth: an intestinal phase in feline hosts, and an extra-intestinal phase in other mammals. Oocysts from an infected cat develop into tachyzoites and, eventually, into bradyzoites and zoitocysts in the extraintestinal host. Transmission of the parasite occurs through contact with infected cats or raw/undercooked meat. In immunocompromised individuals, it can cause severe, often lethal, toxoplasmosis [].Toxoplasma gondii utilise a variety of secretory and antigenic proteins to invade a host and gain access to the intracellular environment. This group represents surface antigen p22 (SAG2) from Toxoplasma gondii [, ].
Chloramphenicol acetyltransferase (CAT) () []catalyzes the acetyl-CoA dependent acetylation of chloramphenicol (Cm), an antibiotic which inhibits prokaryotic peptidyltransferase activity. Acetylation of Cm by CAT inactivates the antibiotic. A histidine residue, located in the C-terminal section of the enzyme, plays a central role in its catalytic mechanism.The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilised by a number of hydrogen bonds, some of which result in the extension of a β-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilisation is provided by an unusual interaction with a main-chain carbonyl oxygen [].
This family is a member of the Class IIA subfamily of the haloacid dehalogenase superfamily of aspartate-nucleophile hydrolases. Sequences in this family are all from eukaryotes. One sequence is called "Cat Eye Syndrome critical region protein 5"(CECR5) []. This gene has been cloned from a pericentromere region of human chromosome 22 believed to be the location of the gene or genes responsible for Cat Eye Syndrome. This is one of a number of candidate genes. The Schizosaccharomyces pombe (Fission yeast) sequence is annotated as "phosphatidyl synthase,"however this is due entirely to a C-terminal region of the protein (outside the region of similarity covered by this entry) which is highly homologous to a family of CDP-alcohol phosphatidyltransferases. The physical connection of the phosphatidyl synthase and the HAD-superfamily hydrolase domain in S. pombe may, however, be an important clue to the substrate for the hydrolases in this group.
Chloramphenicol acetyltransferase (CAT) catalyses the acetyl-CoA dependent acetylation of chloramphenicol, resulting in the inactivation of the antibiotic. The crystal structure of the type III enzyme from Escherichia coli with chloramphenicol bound has been determined. CAT is a trimer of identical subunits (monomer Mr 25,000) and the trimeric structure is stabilised by a number of hydrogen bonds, some of which result in the extension of a β-sheet across the subunit interface. Chloramphenicol binds in a deep pocket located at the boundary between adjacent subunits of the trimer, such that the majority of residues forming the binding pocket belong to one subunit while the catalytically essential histidine belongs to the adjacent subunit. His195 is appropriately positioned to act as a general base catalyst in the reaction, and the required tautomeric stabilisation is provided by an unusual interaction with a main-chain carbonyl oxygen [].This superfamily represents a domain characteristic of trimeric enzymes with the active sites being located in between subunits, including chloramphenicol acetyltransferase.
This entry includes major allergen I polypeptide chain 1 (Fel d 1 chain 1) from cat and related proteins, such as SCGB1B from mice.Allergies are hypersensitivity reactions of the immune system to specific substances called allergens (such as pollen, stings, drugs, or food) that, in most people, result in no symptoms. A nomenclature system has been established for antigens (allergens) that cause IgE-mediated atopic allergies in Homo sapiens (Human). The nomenclature system uses the first three letters of the genus, followed by the first letter of the species name, followed by a number (additional letters can be added to the name as required to discriminate between similar designations).Fel d 1 is allergen 1 from Felis silvestris catus (Cat) which is an important agent in human allergic reactions []. The protein is expressed in saliva and sebaceous glands. The complete primary structure of Fel d 1 has been determined []. The allergen is tetrameric glycoprotein consisting of two disulphide-linked heterodimers of chains 1 and 2, which have been shown to be encoded by different genes. Fel d 1 chains 1 and 2 share structural similarity with uteroglobin, a secretoglobin superfamily member; chain 2 is a glycoprotein with N-linked oligosaccharides.SCGB1B is an androgen-binding protein that plays a role in mate selection in mice [].
This entry includes major allergen I polypeptide chain 2 (Fel d 1 chain 2) from cat and related proteins, such as SCGB2B from mice.Allergies are hypersensitivity reactions of the immune system to specific substances called allergens (such as pollen, stings, drugs, or food) that, in most people, result in no symptoms. A nomenclature system has been established for antigens (allergens) that cause IgE-mediated atopic allergies in humans. The nomenclature system uses the first three letters of the genus, followed by the first letter of the species name, followed by a number (additional letters can be added to the name as required to discriminate between similar designations).Fel d 1 is allergen 1 from Felis silvestris catus (Cat), which is an important agent in human allergic reactions []. The protein is expressed in saliva and sebaceous glands. The complete primary structure of Fel d 1 has been determined []. The allergen is tetrameric glycoprotein consisting of two disulphide-linked heterodimers of chains 1 and 2, which have been shown to be encoded by different genes. Fel d 1 chains 1 and 2 share structural similarity with uteroglobin, a secretoglobin superfamily member; chain 2 is a glycoprotein with N-linked oligosaccharides.SCGB2B is an androgen-binding protein that plays a role in mate selection in mice [].
