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The Walker A and Walker B motifs are protein sequence motifs, known to have highly conserved three-dimensional structures. These were first reported in ATP-binding proteins by Walker and co-workers in 1982. [1] Of the two motifs, the A motif is the main "P-loop" responsible for binding phosphate, while the B motif is a much less conserved ...
An ATP-binding motif is a 250-residue sequence within an ATP -binding protein’s primary structure. The binding motif is associated with a protein’s structure and/or function. [1] ATP is a molecule of energy, and can be a coenzyme, involved in a number of biological reactions. ATP is proficient at interacting with other molecules through a ...
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 ...
This histidine contacts residues across the dimer interface in the Walker A motif and the D loop, a conserved sequence following the Walker B motif. [35] [40] [42] [48] The enzymatic hydrolysis of ATP requires proper binding of the phosphates and positioning of the γ-phosphate to the attacking water. [23]
Beyond this broad function, the Walker motifs can be found in almost all natural ATPases, with the notable exception of tyrosine kinases. [9] The Walker motifs commonly form a Beta sheet-turn-Alpha helix that is self-organized as a Nest (protein structural motif). This is thought to be because modern ATPases evolved from small NTP-binding ...
The P-type ATPases, also known as E 1-E 2 ATPases, are a large group of evolutionarily related ion and lipid pumps that are found in bacteria, archaea, and eukaryotes. [1] P-type ATPases are α-helical bundle primary transporters named based upon their ability to catalyze auto- (or self-) phosphorylation (hence P) of a key conserved aspartate residue within the pump and their energy source ...
Nest (protein structural motif) The Nest is a type of protein structural motif. It is a small recurring anion-binding feature of both proteins and peptides. [1][2][3][4][5][6][7][8][9] Each consists of the main chain atoms of three consecutive amino acid residues. The main chain NH groups bind the anions while the side chain atoms are often not ...
The AAA proteins contain two domains, an N-terminal alpha/beta domain that binds and hydrolyzes nucleotides (a Rossmann fold) and a C-terminal alpha-helical domain. [5] The N-terminal domain is 200-250 amino acids long and contains Walker A and Walker B motifs, [5] and is shared in common with other P-loop NTPases, the superfamily which includes the AAA family. [6]