PIN (PilT N terminus) domain: Superfamily; The PIN (PilT N terminus) domain belongs to a large nuclease superfamily, and were originally named for their sequence similarity to the N-terminal domain of an annotated pili biogenesis protein, PilT, a domain fusion between a PIN-domain and a PilT ATPase domain. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons. The PIN domain superfamily includes: the FEN-like PIN domain family such as the PIN domains of Flap endonuclease-1 (FEN1), exonuclease-1 (EXO1), Mkt1, Gap Endonuclease 1 (GEN1), and Xeroderma pigmentosum complementation group G (XPG) nuclease, 5'-3' exonucleases of DNA polymerase I and bacteriophage T4- and T5-5' nucleases; the VapC-like PIN domain family which includes toxins of prokaryotic toxin/antitoxin operons FitAB and VapBC, as well as eukaryotic ribonucleases such as Smg6, ribosome assembly factor NOB1, exosome subunit Rrp44 endoribonuclease and rRNA-processing protein Fcf1; the LabA-like PIN domain family which includes the PIN domains of Synechococcus elongatus LabA (low-amplitude and bright); the PRORP-Zc3h12a-like PIN domain family which includes the PIN domains of RNase P (PRORP), ribonuclease Zc3h12a; and Bacillus subtilis YacP/Rae1-like PIN domains. It also includes the Mut7-C PIN domain family, which is not represented here as it is a shortened version of the PIN fold and lacks a core strand and helix (H3 and S3). The Mut7-C PIN domain family includes the C-terminus of Caenorhabditis elegans exonuclease Mut-7.

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gi 489053859  10 KPRAPDEALKAFVLTAMHLP--------DDSGFAGIKAAASARDG 46
Cdd:cd18725   80 KPQAADKALKSHIMAVINKGvdclclvsDDSDFGDILRRARRRNL 124

uncharacterized subfamily of the LabA-like PIN domain of Synechococcus elongatus LabA (low-amplitude and bright) and related proteins; The LabA-like PIN domain family includes Synechococcus elongatus PCC 7942 LabA which participates in cyanobacterial circadian timing, it is required for negative feedback regulation of the autokinase/autophosphatase KaiC, a central component of the circadian clock system, and appears to be necessary for KaiC-dependent repression of gene expression. It also includes the N-terminal domain of limkain b1, a human autoantigen localized to a subset of ABCD3 and PXF marked peroxisomes, human ZNF451, uncharacterized Bacillus subtilis YqxD, uncharacterized Escherichia coli YaiI, and the N-terminal domain of a well-conserved group of mainly bacterial proteins with no defined function, which contain a C-terminal LabA_like_C domain. Curiously Pseudomonas putida S16 NicB, which is described as a putative NADH-dependent hydroxylase involved in the microbial degradation of nicotine also falls into this family. The PIN (PilT N terminus) domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

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gi 489053859  10 KPRAPDEALKAFVLTAMHLP--------DDSGFAGIKAAASARDG 46
Cdd:cd18725   80 KPQAADKALKSHIMAVINKGvdclclvsDDSDFGDILRRARRRNL 124

uncharacterized subfamily of the LabA-like PIN domain of Synechococcus elongatus LabA (low-amplitude and bright) and related proteins; The LabA-like PIN domain family includes Synechococcus elongatus PCC 7942 LabA which participates in cyanobacterial circadian timing, it is required for negative feedback regulation of the autokinase/autophosphatase KaiC, a central component of the circadian clock system, and appears to be necessary for KaiC-dependent repression of gene expression. It also includes the N-terminal domain of limkain b1, a human autoantigen localized to a subset of ABCD3 and PXF marked peroxisomes, human ZNF451, uncharacterized Bacillus subtilis YqxD, uncharacterized Escherichia coli YaiI, and the N-terminal domain of a well-conserved group of mainly bacterial proteins with no defined function, which contain a C-terminal LabA_like_C domain. Curiously Pseudomonas putida S16 NicB, which is described as a putative NADH-dependent hydroxylase involved in the microbial degradation of nicotine also falls into this family. The PIN (PilT N terminus) domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its active center, consisting of three highly conserved catalytic residues which coordinate metal ions; in some members, additional metal coordinating residues can be found while some others lack several of these key catalytic residues. The PIN active site is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

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                 ....*....|....*....|....*....|....*....|....*
gi 489053859  10 KPRAPDEALKAFVLTAMHLP--------DDSGFAGIKAAASARDG 46
Cdd:cd18725   80 KPQAADKALKSHIMAVINKGvdclclvsDDSDFGDILRRARRRNL 124