Dihydrofolate reductase; Key enzyme in folate metabolism. Catalyzes an essential reaction for de novo glycine and purine synthesis, and for DNA precursor synthesis.

Modular protein with a N-terminal 7,8-Dihydro-6-hydroxymethylpterin-pyrophosphokinase (HPPK) domain and a C-terminal Deoxyguanosine kinase (DGK) domain. HPPK catalyzes the attachment of pyrophosphate to 6-hydroxymethyl-7,8-dihydropterin to form 6-hydroxymethyl- 7, 8-dihydropteridine pyrophosphate. This is the first step in a three-step pathway leading to 7,8 dihydrofolate. Deoxyguanosine kinase DGK/DAK plays an essential role in generating the deoxyribonucleotide precursors, dGTP and dATP, for DNA metabolism. Localized in the cytoplasm; High confidence in function and specificity.

Thymidylate synthase; Catalyzes the reductive methylation of 2'-deoxyuridine-5'- monophosphate (dUMP) to 2'-deoxythymidine-5'-monophosphate (dTMP) while utilizing 5,10-methylenetetrahydrofolate (mTHF) as the methyl donor and reductant in the reaction, yielding dihydrofolate (DHF) as a by- product. This enzymatic reaction provides an intracellular de novo source of dTMP, an essential precursor for DNA biosynthesis.

TolR, involved in the tonB-independent uptake of biopolymers, forms a complex with the proteins TolQ. This complex energizes TolA from the potential energy of the ion electrochemical gradient. TolA energized, interacts with the outer membrane protein Pal (OprL). The Tol-Pal complex is required for maintaining outer membrane integrity, the transport (uptake) filamentous DNA and is the conduct for bacteriophages; Contains a N-terminal transmembrane helix; Belongs to the exbD/tolR family; Localized in the cytoplasmic membrane; High confidence in function and specificity.

TolQ, involved in the tonB-independent uptake of biopolymers, forms a complex with the proteins TolR. This complex energizes TolA from the potential energy of the ion electrochemical gradient. TolA energized, interacts with the outer membrane protein Pal (OprL). The Tol-Pal complex is required for maintaining outer membrane integrity, the transport (uptake) filamentous DNA and is the conduct for bacteriophages; Contains three transmembrane helices; Belongs to the exbB/tolQ family; Localized in the cytoplasmic membrane; High confidence in function and specificity.

TolA, involved in the tonB-independent uptake of proteins, interacts with the TolQ and TolR, cytoplasmic membrane proteins and with the Pal protein (OprL) in the outer membrane. The transport is energized by the proton motive force. The Tol-Pal complex is required for maintaining outer membrane integrity, the transport (uptake) filamentous DNA and is the conduct for bacteriophages; TolA is anchored to the cytoplasmic membrane by a single transmembrane spanning segment near the N-terminus, leaving most of the protein exposed to the periplasm; High confidence in function and specificity.

GMP synthase [glutamine-hydrolyzing]; Catalyzes the synthesis of GMP from XMP.

Serine hydroxymethyltransferase; Catalyzes the reversible interconversion of serine and glycine with tetrahydrofolate (THF) serving as the one-carbon carrier. This reaction serves as the major source of one-carbon groups required for the biosynthesis of purines, thymidylate, methionine, and other important biomolecules. Also exhibits THF-independent aldolase activity toward beta-hydroxyamino acids, producing glycine and aldehydes, via a retro-aldol mechanism.

Conserved protein belonging to the citrate transporter family, which includes two characterized citrate/proton symporters from Bacillus subtilis. Its exact specificity is unknown. Features eleven transmembrane helices. Localized in the cytoplasmic membrane; Family membership.