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TOG Superfamily
The transporter-opsin-G protein-coupled receptor (TOG) superfamily is a protein superfamily of integral membrane proteins, usually of 7 or 8 transmembrane alpha-helical segments (TMSs). It includes (1) ion-translocating microbial rhodopsins and (2) G protein-coupled receptors (GPCRs), (3) Sweet sugar transporters, (4) nicotinamide ribonucleoside uptake permeases (PnuCTC# 4.B.1, (5) TSUP Family, 4-toluene sulfonate uptake permeases (TSUP)TC# 2.A.102, (6) NiCoT family, Ni2+–Co2+ transporters (NiCoT)TC# 2.A.52, (7) OST Family, organic solute transporters (OST)TC# 2.A.82, (8) Sodium/phosphate cotransporter, phosphate:Na+ symporters (PNaS)TC# 2.A.58 and (9) Lysosomal cystine transporter family, lysosomal cystine transporters (LCT)TC# 2.A.43. Families Currently recognized Protein family, families within the TOG Superfamily (with TCDB, TC numbers in blue) include: 1.A.14- Testis-enhanced gene transfer family, The Testis-enhanced Gene Transfer (TEGT) Family 1.A.26- Magnesium transporter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Superfamily
A protein superfamily is the largest grouping (clade) of proteins for which common ancestry can be inferred (see homology). Usually this common ancestry is inferred from structural alignment and mechanistic similarity, even if no sequence similarity is evident. Sequence homology can then be deduced even if not apparent (due to low sequence similarity). Superfamilies typically contain several protein families which show sequence similarity within each family. The term ''protein clan'' is commonly used for protease and glycosyl hydrolases superfamilies based on the MEROPS and CAZy classification systems. Identification Superfamilies of proteins are identified using a number of methods. Closely related members can be identified by different methods to those needed to group the most evolutionarily divergent members. Sequence similarity Historically, the similarity of different amino acid sequences has been the most common method of inferring homology. Sequence similarity is co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Transporter E
Magnesium transporters E (MgtE) are a family of transmembrane eubacterial MgtE magnesium transporters. Related regions are found also in archaeal and eukaryotic proteins. They have sizes that vary considerably from 311 residues for the ''Methanococcus thermoautotrophicum'' protein, 463 residues for a ''Synechocystis'' homologue, and 513 residues for the human homologue, SLC41A1. These proteins are capable of transporting Mg2+ and Co2+ but not Ni2+. Multiple alignments contain two highly conserved aspartates that may be involved in cation binding. Human transporters from this family are SLC41A1, SLC41A2 and SLC41A3. Structure and Mechanism The ''Bacillus firmus'' transporter and several homologues examined have strongly charged, hydrophilic N-terminal domains (cytoplasmic) followed by a hydrophobic C-terminal domain with 5 putative transmembrane α-helical spanners. A central 100 residues resembles archaeal inositol monophosphate dehydrogenases. Kehres and Maguire sugges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Protein–coupled Receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related proteins that are cell surface receptors that detect molecules outside the cell and activate cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. Text was copied from this source, which is available under Attribution 2.5 Generic (CC BY 2.5) license. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. G protein-coupled receptors are found only in eukaryotes, including yeast, choanoflagellates, and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicotinamide Ribonucleoside Uptake Transporters
The Nicotinamide Ribonucleoside (NR) Uptake Permease (PnuC) FamilyTC# 4.B.1 is a family of transmembrane transporters that is part of the TOG superfamily. Close PnuC homologues are found in a wide range of Gram-negative and Gram-positive bacteria, archaea and eukaryotes. Function PnuC of ''Salmonella typhimurium'' and ''Haemophilus influenzae'' are believed to function cooperatively with NadR homologues, multifunctional proteins that together with PnuC, participate in NR phosphorylation, transport and transcriptional regulation. NadR, a cytoplasmic protein that is partly membrane associated, contains one well conserved and one poorly conserved mononucleotide-binding consensus sequence (G-X4 GKS). It drives transport and may render transport responsive to internal pyridine nucleotide levels. While its N-terminal half functions as a repressor, its C-terminal half functions as an NR kinase in a putative group translocation process. PnuC of ''Haemophilus influenzae'' The ''H. i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbial Rhodopsin
Microbial rhodopsins, also known as bacterial rhodopsins are retinal-binding proteins that provide light-dependent ion transport and sensory functions in halophilic and other bacteria. They are integral membrane proteins with seven transmembrane helices, the last of which contains the attachment point (a conserved lysine) for retinal. This protein family includes light-driven proton pumps, ion pumps and ion channels, as well as light sensors. For example, the proteins from halobacteria include bacteriorhodopsin and archaerhodopsin, which are light-driven proton pumps; halorhodopsin, a light-driven chloride pump; and sensory rhodopsin, which mediates both photoattractant (in the red) and photophobic (in the ultra-violet) responses. Proteins from other bacteria include proteorhodopsin. Contrary to their name, microbial rhodopsins are found not only in Archaea and Bacteria, but also in Eukaryota (such as algae) and viruses; although they are rare in complex multicellular org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SWEET Transporters
The SWEET family (Sugars Will Eventually Be Exported Transporter), also known as the PQ-loop, Saliva or MtN3 familyTC# 2.A.123, is a family of sugar transporters and a member of the TOG superfamily. The proteins of the SWEET family have been found in plants, animals, protozoans, and bacteria. Eukaryotic family members have 7 transmembrane segments (TMSs) in a 3+1+3 repeat arrangement. Function Proteins of the SWEET family appear to catalyze facilitated diffusion (entry or export) of sugars across the plant plasma membrane or the endoplasmic reticulum membrane. They also seem to transport other metabolites, like gibberellins. Transport Reaction The generalized reaction catalyzed by known proteins of this family is: :sugars (in) ⇌ sugars (out) Discovery SWEETs were originally identified in ''Arabidopsis thaliana'', in a screen for novel facilitators of transmembrane glucose transport. In this experiment, several previously uncharacterized membrane proteins were selec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Transporter1 Family
The Magnesium Transporter 1 (MagT1) FamilyTC# 1.A.76 is a group of magnesium transporters that are part of the TOG superfamily. Goytain and Quamme identified a Mg2+-related transporter whose expression or function was affected by an implantation-associated protein precursor. They designated this protein, MagT1. MagT1 is expressed as a 335 amino acid polypeptide which includes five transmembrane helices. The nascent polypeptide possesses a cleavage site after the N-terminal signal sequence helix, rendering a mature MagT1 protein with four transmembrane helices. MagT1 additionally contains a number of phosphorylation sites. Recent evidence demonstrates that the primary function of MagT1 is protein glycosylation, mediated by MagT1's function as a component of the oligosaccharyltransferase (OST). Function When expressed in ''Xenopus laevis'' oocytes, MagT1 mediates saturable Mg2+ uptake with a Km of 0.23 mM. Transport of Mg2+ by MagT1 is rheogenic, voltage-dependent, and does not d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testis-enhanced Gene Transfer Family
The testis-enhanced gene transcript (TEGT) family includes the testis-enhanced gene transcript proteins of mammals, which are expressed at high levels in the testis, the putative glutamate/aspartate binding proteins of plants and animals, the YccA protein of ''Escherichia coli'' and the YetJ protein of ''Bacillus subtilis''. These proteins are about 200-250 residues in length and exhibit 7 TMSs. Homology Homologues are found in a variety of Gram-negative and Gram-positive bacteria, yeast, fungi, plants, animals and viruses. The ''E. coli'' genome encodes three paralogues, YbhL, YbhM and YccA. Distant homologues found in '' Drosophilia melanogaster'' and the rat are the N-methyl-D-aspartate receptor-associated protein (NMDARAI) and the N-methyl-D-aspartate receptor glutamate binding chain, respectively. Two others are the rat neural membrane protein 35 and the '' Arabidopsis thaliana'' Bax inhibitor-1 (BI-1) protein capable of suppressing Bax-induced cell death in yeast. BI-1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Protein
Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane and can either penetrate the membrane (transmembrane) or associate with one or the other side of a membrane ( integral monotopic). Peripheral membrane proteins are transiently associated with the cell membrane. Membrane proteins are common, and medically important—about a third of all human proteins are membrane proteins, and these are targets for more than half of all drugs. Nonetheless, compared to other classes of proteins, determining membrane protein structures remains a challenge in large part due to the difficulty in establishing experimental conditions that can preserve the correct conformation of the protein in isolation from its native environment. Function Membrane proteins perform a variety of functions vital to the sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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