Sandbox Reserved 792

From Proteopedia

proteopedia linkproteopedia link

This Sandbox is Reserved from Oct 10, 2013, through May 20, 2014 for use in the course "CHEM 410 Biochemistry 1 and 2" taught by Hanna Tims at the Messiah College. This reservation includes Sandbox Reserved 780 through Sandbox Reserved 807.

To get started: Click the edit this page tab at the top. Save the page after each step, then edit it again. Click the 3D button (when editing, above the wikitext box) to insert Jmol. show the Scene authoring tools, create a molecular scene, and save it. Copy the green link into the page. Add a description of your scene. Use the buttons above the wikitext box for bold, italics, links, headlines, etc. More help: Help:Editing

spinqualitylabelsall models Citrate Synthase Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Contents 1 Introduction 2 Structure 3 Solvent Interaction 4 Active Site 5 Mechanism of Action 6 References

Introduction

Structure

is a homodimer of its . The A chain is comprised of 429 residues, and with a molecular weight of 51.7 kDa. [1]

The shows the 23 alpha helices (blue-gray) comprise the vast majority of the protein. In contrast, there is only one small anti-parallel beta sheet (orange) per subunit.

The in the backbone are shown in green.

The are shown in grey. The are in pink.

Solvent Interaction

The are shown in blue, the protein in cream and the ligand in a light purple. The water interaction (with the same color designations) are similar in the .

Active Site

The are depicted in ball in stick and the rest of the protein is in ribbon diagram. The is shown in pink. The are shown in black.

Mechanism of Action

The condensation reaction has been proposed to involve two concerted general acid-base catalysis steps, meaning the catalytic residues serve as the general acids and bases needed. The mechanism is also seen to proceed through an enol (rather than an enolate) intermediate, and exhibit an inversion of sterochemistry at the nucleophilic carbon atom [2].

References

1. Kuznetsov, A.V., Lassnig, B., Gnaiger, E. (2010). Laboratory Protocol Citrate Synthase Mitochondrial Marker Enzyme. Mitochondrial Physiology Network 08.14: 1-10.1

2. Karpusas M, Branchaud B, Remington SJ. (1990). Proposed mechanism for the condensation reaction of citrate synthase: 1.9-A structure of the ternary complex with oxaloacetate and carboxymethyl coenzyme A. Biochemistry. Mar 6;29(9):2213-9. 2