Matthew Young (Prof at UMichigan, was a postdoc once upon a time with
John Kuriyan) was in town for BPS. He has some cool new mechanistic
stories on Kinase regulation (and also some new directions on
deubiquitinase inhibitors) that you all might be interested in!

The seminar will be at 4PM Friday (tomorrow) in BH212. Please forward
to your labs!

https://dl.dropboxusercontent.com/u/7403581/matt_young.pdf

If you want to meet with Matt, let me know, he'll get to campus around
2:30-3 and be free until 4. I'm happy to direct him your way - first
come first served! The plan was to grab a beer after the talk at
Terzetto, to which everyone is invited.

Hope to see you there! And apologies for the last minute nature of the invite,

Jaime

ABSTRACT:
Matthew Young - University of Michigan

Allosteric Regulation Of Protein Kinase Enzymes Via An Electrostatic
Switch That Modulates Active Site Dynamics

Protein kinase (PK) enzymes are a large family of signaling proteins
that play a central role in signal transduction pathways. Robust
regulation of their catalytic activity is critical, and many oncogenes
harbor mutations that result in misregulated PK activity. The chemical
basis for how some PK regulatory factors ultimately affect the rate of
chemistry is still not completely understood. We have identified a
long-range electrostatic switch that we believe is used by allosteric
PK regulatory factors to modulate the rate of chemistry by tuning
active-site dynamics.

We applied a combination of crystallography, kinetics, and molecular
dynamics to determine the chemical kinetic basis for how this
electrostatic switch, toggled by regulatory subunit binding, affects
each step of the catalytic cycle of CDK2 kinase. We engineered point
mutants to deconstruct the kinetic, dynamic, and thermodynamic
consequences of the switch. We also evaluated other PKs and find that,
although it has evolved to be triggered in different ways by diverse
PK regulatory factors, the mechanics of this switch can be conserved.

We demonstrate that a key component of the switch is that it affects a
significant change in the electrostatic potential within the ATP*Mg
binding site of the enzyme. This electrostatic effect is propagated
through the low-dielectric protein interior and directly affects the
two dominant rate-determining steps of catalysis: attenuating both the
recruitment of catalytically essential Mg cofactors (affecting both
kcat and KM) as well as the release of the ADP product.

Conclusion: We present a chemical hypothesis that provides a
mechanistic explanation for one way that a large-scale conformation
transition, observed in diverse PK family members, is able to
significantly affect the rate of chemistry by acting at a distance
from the active site.

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--
James Fraser, PhD
Assistant Professor
Department of Bioengineering and Therapeutic Sciences
Office: N212C Genentech Hall, Lab: N216 Genentech Hall
james.fraser@ucsf.edu // jaimefraser@gmail.com
(415) 493-8421
http://www.fraserlab.com