Circadian Clock Protein KaiC

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
==Introduction==
==Introduction==
Biological Circadian Clocks are self-sustaining oscillators that function on a rhythmic cycle of or around 24 hours. The are found in almost all organisms, the simplest of which are cyanobacteria, which have been extensively studied in order to determine the mechanism of the fine-tunes biological process of circadian rhythmicity.
Biological Circadian Clocks are self-sustaining oscillators that function on a rhythmic cycle of or around 24 hours. The are found in almost all organisms, the simplest of which are cyanobacteria, which have been extensively studied in order to determine the mechanism of the fine-tunes biological process of circadian rhythmicity.
 +
 +
==KaiC - KaiA - KaiB System==
 +
KaiC is the central clock protein but cannot perform it's function alone. It requires two other proteins, KaiA and KaiB, the genes of which are found in the same cluster on the chromosome (1). Although KaiC has autokinase and autophosphorylation functions, the presence of KaiA and KaiB are essential to rhythmicity. KaiA stimulates KaiC autophosphorylation, while KaiB antagonizes the process possibly by enhancing KaiC dephosphorylation. Even in the presence of high ATP, KaiB still prompts KaiC to dephosphorylate.
== KaiC Homohexameric Complex ==
== KaiC Homohexameric Complex ==
Line 8: Line 11:
</StructureSection>
</StructureSection>
 +
==KaiC Autophosphorylation Sites==
 +
(difference between ATP binding and phosphorylation residues)
 +
(Key residues = T432, S431, T426)
 +
(show 3D image of these sites and highlight bonds/interactions)
 +
 +
==KaiA <-> KaiC Interaction Site==
 +
(show 3D image of KaiC site for KaiA binding and highlight key residues in interaction -weak? strong? any ions in site? how does it stabilize autophosporylation?)
 +
 +
==KaiB <-> KaiC Interaction Site==
 +
(show 3D image of KaiC site for KaiB binding and highlight key residues in interaction -weak? strong? ions in site? how does it stabilize dephosphorylation/destabilize phosphorylation/destabilize KaiA?)
==Biological Importance==
==Biological Importance==
- Nearly all promoters in a cyanobacteria are under circadian control. [function is important to whole life cycle] (1)
- Nearly all promoters in a cyanobacteria are under circadian control. [function is important to whole life cycle] (1)

Revision as of 17:28, 29 November 2012

Contents

Introduction

Biological Circadian Clocks are self-sustaining oscillators that function on a rhythmic cycle of or around 24 hours. The are found in almost all organisms, the simplest of which are cyanobacteria, which have been extensively studied in order to determine the mechanism of the fine-tunes biological process of circadian rhythmicity.

KaiC - KaiA - KaiB System

KaiC is the central clock protein but cannot perform it's function alone. It requires two other proteins, KaiA and KaiB, the genes of which are found in the same cluster on the chromosome (1). Although KaiC has autokinase and autophosphorylation functions, the presence of KaiA and KaiB are essential to rhythmicity. KaiA stimulates KaiC autophosphorylation, while KaiB antagonizes the process possibly by enhancing KaiC dephosphorylation. Even in the presence of high ATP, KaiB still prompts KaiC to dephosphorylate.

KaiC Homohexameric Complex

Structure of KaiC (PDB entry 1TF7)

Drag the structure with the mouse to rotate

KaiC Autophosphorylation Sites

(difference between ATP binding and phosphorylation residues) (Key residues = T432, S431, T426) (show 3D image of these sites and highlight bonds/interactions)

KaiA <-> KaiC Interaction Site

(show 3D image of KaiC site for KaiA binding and highlight key residues in interaction -weak? strong? any ions in site? how does it stabilize autophosporylation?)

KaiB <-> KaiC Interaction Site

(show 3D image of KaiC site for KaiB binding and highlight key residues in interaction -weak? strong? ions in site? how does it stabilize dephosphorylation/destabilize phosphorylation/destabilize KaiA?)

Biological Importance

- Nearly all promoters in a cyanobacteria are under circadian control. [function is important to whole life cycle] (1)

Proteopedia Page Contributors and Editors (what is this?)

Ashley Beechan, Michal Harel, Alexander Berchansky, Jaime Prilusky

Personal tools