4NKY

Human steroidogenic cytochrome P450 17A1 mutant A105L with substrate 17alpha-hydroxyprogesterone


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.182 

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Literature

Structures of Human Steroidogenic Cytochrome P450 17A1 with Substrates.

Petrunak, E.M.DeVore, N.M.Porubsky, P.R.Scott, E.E.

(2014) J Biol Chem 289: 32952-32964

  • DOI: 10.1074/jbc.M114.610998
  • Primary Citation of Related Structures:  
    4NKY, 4NKZ, 4NKV, 4NKW, 4NKX

  • PubMed Abstract: 
  • The human cytochrome P450 17A1 (CYP17A1) enzyme operates at a key juncture of human steroidogenesis, controlling the levels of mineralocorticoids influencing blood pressure, glucocorticoids involved in immune and stress responses, and androgens and estrogens involved in development and homeostasis of reproductive tissues ...

    The human cytochrome P450 17A1 (CYP17A1) enzyme operates at a key juncture of human steroidogenesis, controlling the levels of mineralocorticoids influencing blood pressure, glucocorticoids involved in immune and stress responses, and androgens and estrogens involved in development and homeostasis of reproductive tissues. Understanding CYP17A1 multifunctional biochemistry is thus integral to treating prostate and breast cancer, subfertility, blood pressure, and other diseases. CYP17A1 structures with all four physiologically relevant steroid substrates suggest answers to four fundamental aspects of CYP17A1 function. First, all substrates bind in a similar overall orientation, rising ∼60° with respect to the heme. Second, both hydroxylase substrates pregnenolone and progesterone hydrogen bond to Asn(202) in orientations consistent with production of 17α-hydroxy major metabolites, but functional and structural evidence for an A105L mutation suggests that a minor conformation may yield the minor 16α-hydroxyprogesterone metabolite. Third, substrate specificity of the subsequent 17,20-lyase reaction may be explained by variation in substrate height above the heme. Although 17α-hydroxyprogesterone is only observed farther from the catalytic iron, 17α-hydroxypregnenolone is also observed closer to the heme. In conjunction with spectroscopic evidence, this suggests that only 17α-hydroxypregnenolone approaches and interacts with the proximal oxygen of the catalytic iron-peroxy intermediate, yielding efficient production of dehydroepiandrosterone as the key intermediate in human testosterone and estrogen synthesis. Fourth, differential positioning of 17α-hydroxypregnenolone offers a mechanism whereby allosteric binding of cytochrome b5 might selectively enhance the lyase reaction. In aggregate, these structures provide a structural basis for understanding multiple key reactions at the heart of human steroidogenesis.


    Organizational Affiliation

    From the Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045 and eescott@ku.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Steroid 17-alpha-hydroxylase/17,20 lyaseA, B, C, D494Homo sapiensMutation(s): 1 
Gene Names: CYP17CYP17A1S17AH
EC: 1.14.99.9 (PDB Primary Data), 4.1.2.30 (PDB Primary Data), 1.14.14.19 (UniProt), 1.14.14.32 (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for P05093 (Homo sapiens)
Explore P05093 
Go to UniProtKB:  P05093
PHAROS:  P05093
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.182 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.285α = 90
b = 151.778β = 90
c = 168.045γ = 90
Software Package:
Software NamePurpose
Blu-Icedata collection
PHASERphasing
PHENIXrefinement
XDSdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-10-22
    Type: Initial release
  • Version 1.1: 2014-12-03
    Changes: Database references