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==Binding Interactions==
==Binding Interactions==


<scene name='48/483888/Spacefilled_binding_site/1'>Space filling representation of residues that bind with Vitamin D3</scene>
The binding of Vitamin D3 occurs in a channel between the G and I helices and B' helix and B-C loop. In the <scene name='48/483888/Spacefilled_binding_site/1'>Space filling representation </scene> you can see the residues that interact to bind Vitamin D3 and the channel between. Most of these residues are hydrophobic and thus have non polar interactions. Binding of the substrate causes the access channel to close. The B' helix has a flexible C terminus and can adopt a helix or loop conformation, which has van der waal interactions with the F-G loop. The B' helix unwinds outward to allow entrance of the substrate into the active site channel. CYP2R1 has an extended binding site where the access channel is part of the active site.
-catalyzes initial step for converting vitamin D into 25-hydroxyvitamin D
-catalyzes initial step for converting vitamin D into 25-hydroxyvitamin D
-mutation causes rickets-25-hydroxylase deficiency
-mutation causes rickets-25-hydroxylase deficiency
-has closed conformation, substrate access channel mostly covered
 
-secosteroid binding, extended active site
 





Revision as of 15:37, 7 April 2016


This Sandbox is Reserved from January 19, 2016, through August 31, 2016 for use for Proteopedia Team Projects by the class Chemistry 423 Biochemistry for Chemists taught by Lynmarie K Thompson at University of Massachusetts Amherst, USA. This reservation includes Sandbox Reserved 425 through Sandbox Reserved 439.


Vitamin D activation by cytochrome P450, Rickets (3c6g)[1]

by Isabel Hand, Elizabeth Humble, Kati Johnson, Samantha Kriksceonaitis, and Matthew Tiller

Student Projects for UMass Chemistry 423 Spring 2016 <StructureSection load='3c6g' size='350' side='right' caption='caption for Molecular Playground (PDB entry 3c6g)' scene=>

Introduction

Rickets is a disease caused by a vitamin D deficiency. Vitamin D can be obtained from ultra violet radiation and from various food sources. Cytochrome P450 enzymes are involved in the first step to regulate and process vitamin D in the human body. Human P450

Overall Structure

- Asymmetric dimer
- Consists of α-helices, β-sheets (mostly on one side of the molecule) with a heme buried inside the protein
- Two molecules of 2-hydroxypropyl-β-cyclodextrin are found near the dimer interface


Binding Interactions

The binding of Vitamin D3 occurs in a channel between the G and I helices and B' helix and B-C loop. In the Space filling representation you can see the residues that interact to bind Vitamin D3 and the channel between. Most of these residues are hydrophobic and thus have non polar interactions. Binding of the substrate causes the access channel to close. The B' helix has a flexible C terminus and can adopt a helix or loop conformation, which has van der waal interactions with the F-G loop. The B' helix unwinds outward to allow entrance of the substrate into the active site channel. CYP2R1 has an extended binding site where the access channel is part of the active site. -catalyzes initial step for converting vitamin D into 25-hydroxyvitamin D -mutation causes rickets-25-hydroxylase deficiency



Additional Features

This molecule has a heme which is bound to iron, which, combined with its structural conformation, allows for hydroxylation with the attached substrate. This molecule carries out important functions and is not species or sex specific.


Heme Group


Quiz Question 1

(merely an example of what this section might look like)


rom this orientation can you identify the green, red, and blue parts of the molecule?

See Also

Credits

Introduction - Sami Kriksceonaitis

Overall Structure - Kati Johnson

Drug Binding Site - Isabel Hand

Additional Features - Elizabeth Humble

Quiz Question 1 - Matthew Tiller1

References

  1. ↑ Strushkevich N, Usanov SA, Plotnikov AN, Jones G, Park HW. Structural analysis of CYP2R1 in complex with vitamin D3. J Mol Biol. 2008 Jun 27;380(1):95-106. Epub 2008 Apr 8. PMID:18511070 doi:10.1016/j.jmb.2008.03.065