HHsearch alignment for GI: 254780648 and conserved domain: TIGR01277

>TIGR01277 thiQ thiamine ABC transporter, ATP-binding protein; InterPro: IPR005968 ABC transporters belong to the ATP-Binding Cassette (ABC) superfamily, which uses the hydrolysis of ATP to energize diverse biological systems. ABC transporters are minimally constituted of two conserved regions: a highly conserved ATP binding cassette (ABC) and a less conserved transmembrane domain (TMD). These regions can be found on the same protein or on two different ones. Most ABC transporters function as a dimer and therefore are constituted of four domains, two ABC modules and two TMDs. ABC transporters are involved in the export or import of a wide variety of substrates ranging from small ions to macromolecules. The major function of ABC import systems is to provide essential nutrients to bacteria. They are found only in prokaryotes and their four constitutive domains are usually encoded by independent polypeptides (two ABC proteins and two TMD proteins). Prokaryotic importers require additional extracytoplasmic binding proteins (one or more per systems) for function. In contrast, export systems are involved in the extrusion of noxious substances, the export of extracellular toxins and the targeting of membrane components. They are found in all living organisms and in general the TMD is fused to the ABC module in a variety of combinations. Some eukaryotic exporters encode the four domains on the same polypeptide chain . The ABC module (approximately two hundred amino acid residues) is known to bind and hydrolyze ATP, thereby coupling transport to ATP hydrolysis in a large number of biological processes. The cassette is duplicated in several subfamilies. Its primary sequence is highly conserved, displaying a typical phosphate-binding loop: Walker A, and a magnesium binding site: Walker B. Besides these two regions, three other conserved motifs are present in the ABC cassette: the switch region which contains a histidine loop, postulated to polarize the attaching water molecule for hydrolysis, the signature conserved motif (LSGGQ) specific to the ABC transporter, and the Q-motif (between Walker A and the signature), which interacts with the gamma phosphate through a water bond. The Walker A, Walker B, Q-loop and switch region form the nucleotide binding site , , . The 3D structure of a monomeric ABC module adopts a stubby L-shape with two distinct arms. ArmI (mainly beta-strand) contains Walker A and Walker B. The important residues for ATP hydrolysis and/or binding are located in the P-loop. The ATP-binding pocket is located at the extremity of armI. The perpendicular armII contains mostly the alpha helical subdomain with the signature motif. It only seems to be required for structural integrity of the ABC module. ArmII is in direct contact with the TMD. The hinge between armI and armII contains both the histidine loop and the Q-loop, making contact with the gamma phosphate of the ATP molecule. ATP hydrolysis leads to a conformational change that could facilitate ADP release. In the dimer the two ABC cassettes contact each other through hydrophobic interactions at the antiparallel beta-sheet of armI by a two-fold axis , , , , , . Proteins known to belong to this family are classified in several functional subfamilies depending on the substrate used (for further information see http://www.tcdb.org/tcdb/index.php?tc=3.A.1). Thiamine pyrophosphate (TPP) is a required cofactor synthesized de novo in Salmonella typhimurium. The primary role for TPP is in central metabolism as an electron carrier and nucleophile for such enzymes as pyruvate dehydrogenase ( from EC), acetolactate synthase ( from EC), and alpha-ketoglutarate dehydrogenase ( from EC). Despite its importance in cellular physiology, neither the de novo biosynthetic pathway nor the salvage systems for thiamine are fully understood in any organism. The model describes thiamine ABC transporter, ATP-binding protein, believed to be involved in the specific translocation of thiamine and its phosphoesters across the inner membrane The protein belongs to the larger ABC transport system which consists of at least three components: the inner membrane permease; thiamine binding protein and an ATP-binding subunit. This protein is found so far only in Proteobacteria, and is found in complete genomes only if the ThiB and ThiP subunits are also found. It has been experimentally demonstrated that mutants in the various steps in the de novo synthesis of thiamine and its biologically active form, namely thiamine pyrophosphate can be exogenously supplemented with thiamine, thiamine monophosphate or thiamine pyrophosphate. ; GO: 0005524 ATP binding, 0042626 ATPase activity coupled to transmembrane movement of substances, 0006810 transport, 0009276 1-2nm peptidoglycan-based cell wall.
Probab=95.41  E-value=0.0045  Score=38.46  Aligned_cols=38  Identities=34%  Similarity=0.477  Sum_probs=26.1

Q ss_conf             0112442167775303541014540121211000000102663298689
Q Consensus       160 aDVglVG~PNaGKSTLln~ls~ak~kIa~ypFTT~~P~lGvv~~~~~~~  208 (335)
T Consensus        25 e~VAi~GpSGAGKSTLLnLiAGF-----------~~PasG~i~~nd~~~   62 (213)
T ss_conf             76888758986278898778640-----------477640588778012