Y-27632 2HCl Mechanism
The ROCK consists of an N-terminal region, a kinase catalytic domain, a RhoA binding domain, and a pleckstrin homology domain. Among them, the C-terminal region of ROCK binds to and inhibits the kinase catalytic domains, while two N-terminal regions form a dimerization domain linking two kinase domains and interacts with a dimeric inhibitory domain. In addition, the kinase domain of ROCK consists of two lobes (N- lobe and C- lobe) linked by a hinge region. At the interface between these two domains, the ATP-binding pocket of the active site is formed by a groove and is enclosed by the hinge region, the glycine-rich loop, and the activation loop. [1]
The crystal structure reveals that Y-27632 binds in the ATP binding pocket. Specifically, the pyridine ring occupies the same space as the adenine six-member ring of ATP in the kinase. A hydrogen bond is formed between the pyridine nitrogen and the amide nitrogen of Met156, and an aromatic carbon donates a hydrogen bond to the Glu154 main chain carbonyl. [2] The amide carbonyl of Y-27632 interacts with the protein via a bound water molecule that in turn forms a hydrogen bond to the main chain amide nitrogen of Asp216. Primary amines are quite basic, and therefore interact with the side chains of Asn203 and Asp216 residues that normally coordinate Mg ions in kinase structures with bound ATP or ATP analogs. [1]
References
[1] Jacobs M, et al. J Biol Chem. 2006, 281(1), 260-268.
[2] Pierce AC, et al. Proteins. 2002, 49(4), 567-576.
in vivo invitation
