Walker motifs

P-loop containing nucleoside triphosphate hydrolase
P-loop containing nucleoside triphosphate hydrolase
Identifiers
Symbol	?
InterPro	IPR027417

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 downstream region. The P-loop is best known for its presence in ATP- and GTP-binding proteins, and is also found in a variety of proteins with phosphorylated substrates. Major lineages include:^[2]^[3]^[4]^[5]

RecA and rotor ATP synthase / ATPases (α and β subunits).
Nucleic acid-dependent ATPases: helicases, Swi2, and PhoH (InterPro: IPR003714)
AAA proteins
STAND NTPases including MJ, PH, AP, and NACHT ATPases
ABC-PilT ATPases
Nucleotide kinases (InterPro: IPR000850)
G domain proteins: G-proteins (transducin), myosin.

^ Walker JE, Saraste M, Runswick MJ, Gay NJ (1982). "Distantly related sequences in the alpha- and beta-subunits of ATP synthase, myosin, kinases and other ATP-requiring enzymes and a common nucleotide binding fold". The EMBO Journal. 1 (8): 945–951. doi:10.1002/j.1460-2075.1982.tb01276.x. PMC 553140. PMID 6329717.
^ Leipe DD, Wolf YI, Koonin EV, Aravind L (March 2002). "Classification and evolution of P-loop GTPases and related ATPases". Journal of Molecular Biology. 317 (1): 41–72. doi:10.1006/jmbi.2001.5378. PMID 11916378.
^ Stryer L, Berg JM, Tymoczko JL (2002). Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4684-0.
^ Ramakrishnan C, Dani VS, Ramasarma T (October 2002). "A conformational analysis of Walker motif A [GXXXXGKT (S)] in nucleotide-binding and other proteins". Protein Engineering. 15 (10): 783–798. doi:10.1093/protein/15.10.783. PMID 12468712.
^ Saraste M, Sibbald PR, Wittinghofer A (November 1990). "The P-loop--a common motif in ATP- and GTP-binding proteins". Trends in Biochemical Sciences. 15 (11): 430–434. doi:10.1016/0968-0004(90)90281-f. PMID 2126155.

[pmid6329717-1] Walker JE, Saraste M, Runswick MJ, Gay NJ (1982). "Distantly related sequences in the alpha- and beta-subunits of ATP synthase, myosin, kinases and other ATP-requiring enzymes and a common nucleotide binding fold". The EMBO Journal. 1 (8): 945–951. doi:10.1002/j.1460-2075.1982.tb01276.x. PMC 553140. PMID 6329717.

[pmid11916378-2] Leipe DD, Wolf YI, Koonin EV, Aravind L (March 2002). "Classification and evolution of P-loop GTPases and related ATPases". Journal of Molecular Biology. 317 (1): 41–72. doi:10.1006/jmbi.2001.5378. PMID 11916378.

[isbn0-7167-4684-0-3] Stryer L, Berg JM, Tymoczko JL (2002). Biochemistry. San Francisco: W.H. Freeman. ISBN 0-7167-4684-0.

[4] Ramakrishnan C, Dani VS, Ramasarma T (October 2002). "A conformational analysis of Walker motif A [GXXXXGKT (S)] in nucleotide-binding and other proteins". Protein Engineering. 15 (10): 783–798. doi:10.1093/protein/15.10.783. PMID 12468712.

[pmid2126155-5] Saraste M, Sibbald PR, Wittinghofer A (November 1990). "The P-loop--a common motif in ATP- and GTP-binding proteins". Trends in Biochemical Sciences. 15 (11): 430–434. doi:10.1016/0968-0004(90)90281-f. PMID 2126155.

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