This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
3q53 is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
p21-activated kinases (PAKs) play an important role in diverse cellular processes. Full activation of PAKs requires autophosphorylation of a critical threonine/serine located in the activation loop of the kinase domain. Here we report crystal structures of the phosphorylated and unphosphorylated PAK1 kinase domain. The phosphorylated PAK1 kinase domain has a conformation typical of all active protein kinases. Interestingly, the structure of the unphosphorylated PAK1 kinase domain reveals an unusual dimeric arrangement expected in an authentic enzyme-substrate complex, in which the activation loop of the putative "substrate" is projected into the active site of the "enzyme." The enzyme is bound to AMP-PNP and has an active conformation, whereas the substrate is empty and adopts an inactive conformation. Thus, the structure of the asymmetric homodimer mimics a trans-autophosphorylation complex, and suggests that unphosphorylated PAK1 could dynamically adopt both the active and inactive conformations in solution.
Structural insights into the autoactivation mechanism of p21-activated protein kinase.,Wang J, Wu JW, Wang ZX Structure. 2011 Dec 7;19(12):1752-61. PMID:22153498[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Wang J, Wu JW, Wang ZX. Structural insights into the autoactivation mechanism of p21-activated protein kinase. Structure. 2011 Dec 7;19(12):1752-61. PMID:22153498 doi:10.1016/j.str.2011.10.013
