Identification of substrate binding site of cyclin-dependent kinase 5.
Cyclin-dependent kinase 5 (CDK5), unlike other CDKs, is active only in neuronal cells where its neuron-specific activator p35 is present. However, it phosphorylates serines/threonines in S/TPXK/R-type motifs like other CDKs. The tail portion of neurofilament-H contains more than 50 KSP repeats, and CDK5 has been shown to phosphorylate S/T specifically only in KS/TPXK motifs, indicating highly specific interactions in substrate recognition. CDKs have been shown to have a high preference for a basic residue (lysine or arginine) as the n+3 residue, n being the location in the primary sequence of a phosphoacceptor serine or threonine. Because of the lack of a crystal structure of a CDK-substrate complex, the structural basis for this specific interaction is unknown. We have used site-directed mutagenesis ("charged to alanine") and molecular modeling techniques to probe the recognition interactions for substrate peptide (PKTPKKAKKL) derived from histone H1 docked in the active site of CDK5. The experimental data and computer simulations suggest that Asp86 and Asp91 are key residues that interact with the lysines at positions n+2 and/or n+3 of the substrates.
Sharma
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Laboratory of Neurochemistry NINDS, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Steinbach
P J
PJ
Sharma
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M
Amin
N D
ND
Barchi
J J
JJ
Pant
H C
HC
D000595:Amino Acid Sequence; D001216:Asparagine / Q000378:metabolism; D001665:Binding Sites; D042846:CDC2-CDC28 Kinases; D003198:Computer Simulation; D051357:Cyclin-Dependent Kinase 2; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D001216:Asparagine; D051360:Cyclin-Dependent Kinase 5; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases