ACT domain, binds amino acids and other small ligands [Signal transduction mechanisms];

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1576499609  15 ILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIP-FNASIDRLKEKMSYLCNELGLEVSF 88
Cdd:COG3830     5 ALITVTGKDRPGITAAVSGVLAEHGVNILDISQTVIHGYFTMGMLVDLPeSSASFEELQKDLEAAGEELGVEVRV 79

ACT domain-containing protein;

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1576499609 17 ITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIP-FNASIDRLKEKMSYLCNELGLEV 86
Cdd:PRK00194   6 ITVIGKDKVGIIAGVSTVLAELNVNILDISQTIMDGYFTMIMLVDISeSKKDFAELKEELEELGKELGVKI 76

ACT domain, binds amino acids and other small ligands [Signal transduction mechanisms];

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1576499609  15 ILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIP-FNASIDRLKEKMSYLCNELGLEVSF 88
Cdd:COG3830     5 ALITVTGKDRPGITAAVSGVLAEHGVNILDISQTVIHGYFTMGMLVDLPeSSASFEELQKDLEAAGEELGVEVRV 79

Glycine cleavage system regulator GcvR [Amino acid transport and metabolism];

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1576499609  14 YILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIPFNAsIDRLKEKMSYLCNELGLEVSF 88
Cdd:COG2716     3 HLVITAIGPDRPGIVAALARAVSEHGCNILDSRMARLGGEFAGILLVSGPWDA-IAKLEAALPALAAELGLLVTV 76

ACT domain proteins similar to the yet uncharacterized Streptococcus pneumoniae ACT domain protein; This CD, ACT_1ZPV, includes those single ACT domain proteins similar to the yet uncharacterized Streptococcus pneumoniae ACT domain protein (pdb structure 1ZPV). Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1576499609 15 ILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIP-FNASIDRLKEKMSYLCNELGLEVS 87
Cdd:cd04872    2 AVITVVGKDRVGIVAGVSTKLAELNVNILDISQTIMDGYFTMIMIVDISeSNLDFAELQEELEELGKELGVKIR 75

ACT domains that comprise the Glycine Cleavage System Transcriptional Repressor (GcvR) protein, and other related domains; This CD includes the first of the two ACT domains that comprise the Glycine Cleavage System Transcriptional Repressor (GcvR) protein, and other related domains. The glycine cleavage enzyme system in Escherichia coli provides one-carbon units for cellular methylation reactions. This enzyme system, encoded by the gcvTHP operon and lpd gene, catalyzes the cleavage of glycine into CO2 + NH3 and transfers a one-carbon unit to tetrahydrofolate, producing 5,10-methylenetetrahydrofolate. The gcvTHP operon is activated by the GcvA protein in response to glycine and repressed by a GcvA/GcvR interaction in the absence of glycine. It has been proposed that the co-activator glycine acts through a mechanism of de-repression by binding to GcvR and preventing GcvR from interacting with GcvA to block GcvA's activator function. Evidence also suggests that GcvR interacts directly with GcvA rather than binding to DNA to cause repression. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1576499609 14 YILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIPFNAsIDRLKEKMSYLCNELGL 84
Cdd:cd04893    1 HLVISALGTDRPGILNELTRAVSESGCNILDSRMAILGTEFALTMLVEGSWDA-IAKLEAALPGLARRLDL 70

ACT domains are commonly involved in specifically binding an amino acid or other small ligand leading to regulation of the enzyme; Members of this CD belong to the superfamily of ACT regulatory domains. Pairs of ACT domains are commonly involved in specifically binding an amino acid or other small ligand leading to regulation of the enzyme. The ACT domain has been detected in a number of diverse proteins; some of these proteins are involved in amino acid and purine biosynthesis, phenylalanine hydroxylation, regulation of bacterial metabolism and transcription, and many remain to be characterized. ACT domain-containing enzymes involved in amino acid and purine synthesis are in many cases allosteric enzymes with complex regulation enforced by the binding of ligands. The ACT domain is commonly involved in the binding of a small regulatory molecule, such as the amino acids L-Ser and L-Phe in the case of D-3-phosphoglycerate dehydrogenase and the bifunctional chorismate mutase-prephenate dehydratase enzyme (P-protein), respectively. Aspartokinases typically consist of two C-terminal ACT domains in a tandem repeat, but the second ACT domain is inserted within the first, resulting in, what is normally the terminal beta strand of ACT2, formed from a region N-terminal of ACT1. ACT domain repeats have been shown to have nonequivalent ligand-binding sites with complex regulatory patterns such as those seen in the bifunctional enzyme, aspartokinase-homoserine dehydrogenase (ThrA). In other enzymes, such as phenylalanine hydroxylases, the ACT domain appears to function as a flexible small module providing allosteric regulation via transmission of conformational changes, these conformational changes are not necessarily initiated by regulatory ligand binding at the ACT domain itself. ACT domains are present either singularly, N- or C-terminal, or in pairs present C-terminal or between two catalytic domains. Unique to cyanobacteria are four ACT domains C-terminal to an aspartokinase domain. A few proteins are composed almost entirely of ACT domain repeats as seen in the four ACT domain protein, the ACR protein, found in higher plants; and the two ACT domain protein, the glycine cleavage system transcriptional repressor (GcvR) protein, found in some bacteria. Also seen are single ACT domain proteins similar to the Streptococcus pneumoniae ACT domain protein (uncharacterized pdb structure 1ZPV) found in both bacteria and archaea. Purportedly, the ACT domain is an evolutionarily mobile ligand binding regulatory module that has been fused to different enzymes at various times.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 1576499609 17 ITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIPFNASIDRLKEKM 75
Cdd:cd02116    1 LTVSGPDRPGLLAKVLSVLAEAGINITSIEQRTSGDGGEADIFIVVDGDGDLEKLLEAL 59

ACT domain; This family of domains generally have a regulatory role. ACT domains are linked to a wide range of metabolic enzymes that are regulated by amino acid concentration. Pairs of ACT domains bind specifically to a particular amino acid leading to regulation of the linked enzyme. The ACT domain is found in: D-3-phosphoglycerate dehydrogenase EC:1.1.1.95, which is inhibited by serine. Aspartokinase EC:2.7.2.4, which is regulated by lysine. Acetolactate synthase small regulatory subunit, which is inhibited by valine. Phenylalanine-4-hydroxylase EC:1.14.16.1, which is regulated by phenylalanine. Prephenate dehydrogenase EC:4.2.1.51. formyltetrahydrofolate deformylase EC:3.5.1.10, which is activated by methionine and inhibited by glycine. GTP pyrophosphokinase EC:2.7.6.5

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1576499609 15 ILITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMKNIFILSMLVKIPFNASIDRLKEKMSYLCN 80
Cdd:pfam01842  1 TVLEVLVPDRPGLLARVLGALADRGINITSIEQGTSEDKGGIVFVVIVVDEEDLEEVLEALKKLEG 66

ACT domains of the bacterial signal-transducing uridylyltransferase /uridylyl-removing (UUR) enzyme, GlnD; This ACT domain family, ACT_UUR_ACR-like, includes the two C-terminal ACT domains of the bacterial signal-transducing uridylyltransferase /uridylyl-removing (UUR) enzyme, GlnD; including those enzymes similar to the GlnD found in enteric Escherichia coli and those found in photosynthetic, nitrogen-fixing bacterium Rhodospirillum rubrum. Also included in this CD are the four ACT domains of a novel protein composed almost entirely of ACT domain repeats (the ACR protein) and like proteins. These ACR proteins, found in Arabidopsis and Oryza, are proposed to function as novel regulatory or sensor proteins in plants. This CD also includes the first of the two ACT domains that comprise the Glycine Cleavage System Transcriptional Repressor (GcvR) protein and related domains, as well as, the N-terminal ACT domain of a yet characterized Arabidopsis/Oryza predicted tyrosine kinase. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20
                 ....*....|....*....|....*....
gi 1576499609 16 LITAVGPNRPGLIAEISSIIAEFGYNIED 44
Cdd:cd04873    2 VVEVYAPDRPGLLADITRVLADLGLNIHD 30

ACT domain; ACT domains bind to amino acids and regulate associated enzyme domains. These ACT domains are found at the C-terminus of the RelA protein.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1576499609 17 ITAVGPNRPGLIAEISSIIAEFGYNIEDLDQVVMK--NIFILSMLVKIPFNASIDRLKEKM 75
Cdd:pfam13291  8 LEVEAIDRPGLLADITQVISEEKANIVSVNAKTRKkdGTAEIKITLEVKDVEHLERLMAKL 68

(p)ppGpp synthase/hydrolase, HD superfamily [Signal transduction mechanisms, Transcription];

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1576499609  15 ILITAVgpNRPGLIAEISSIIAEFGYNIEDLD-QVVMKNIFILSMLVKIpfnASIDRLKEKMSYL 78
Cdd:COG0317   649 IRIEAL--DRPGLLADITSVIAEEKINILSVNtRSRDDGTATIRFTVEV---RDLDHLARVLRKL 708

C-terminal ACT (regulatory) domain of D-3-Phosphoglycerate Dehydrogenase (3PGDH) found in fungi and bacteria; The C-terminal ACT (regulatory) domain of D-3-Phosphoglycerate Dehydrogenase (3PGDH) found in fungi and bacteria. 3PGDH is an enzyme that belongs to the D-isomer specific, 2-hydroxyacid dehydrogenase family and catalyzes the oxidation of D-3-phosphoglycerate to 3- phosphohydroxypyruvate, which is the first step in the biosynthesis of L-serine, using NAD+ as the oxidizing agent. In Escherichia coli, the SerA 3PGDH is feedback-controlled by the end product L-serine in an allosteric manner. In the homotetrameric enzyme, the interface at adjacent ACT (regulatory) domains couples to create an extended beta-sheet. Each regulatory interface forms two serine-binding sites. The mechanism by which serine transmits inhibition to the active site is postulated to involve the tethering of the regulatory domains together to create a rigid quaternary structure with a solvent-exposed active site cleft. Members of this CD belong to the superfamily of ACT regulatory domains.

                         10        20
                 ....*....|....*....|....*...
gi 1576499609 17 ITAVGPNRPGLIAEISSIIAEFGYNIED 44
Cdd:cd04901    2 ILHIHKNVPGVLGQINTILAEHNINIAA 29