4AE6

Structure and Function of the Human Sperm-Specific Isoform of Protein Kinase A (PKA) Catalytic Subunit Calpha 2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure and Function of the Human Sperm-Specific Isoform of Protein Kinase a (Pka) Catalytic Subunit Calpha2

Hereng, T.H.Backe, P.H.Kahmann, J.Scheich, C.Bjoras, M.Skalhegg, B.S.Rosendal, K.R.

(2012) J.Struct.Biol. 178: 300

  • DOI: 10.1016/j.jsb.2012.03.013
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Protein kinase A (PKA) exists as several tissue-specific isoforms that through phosphorylation of serine and threonine residues of substrate proteins act as key regulators of a number of cellular processes. We here demonstrate that the human sperm-sp ...

    Protein kinase A (PKA) exists as several tissue-specific isoforms that through phosphorylation of serine and threonine residues of substrate proteins act as key regulators of a number of cellular processes. We here demonstrate that the human sperm-specific isoform of PKA named Cα2 is important for sperm motility and thus male fertility. Furthermore, we report on the first three-dimensional crystal structure of human apo Cα2 to 2.1 Å. Apo Cα2 displays an open conformation similar to the well-characterized apo structure of murine Cα1. The asymmetric unit contains two molecules and the core of the small lobe is rotated by almost 13° in the A molecule relative to the B molecule. In addition, a salt bridge between Lys72 and Glu91 was observed for Cα2 in the apo-form, a conformation previously found only in dimeric or ternary complexes of Cα1. Human Cα2 and Cα1 share primary structure with the exception of the amino acids at the N-terminus coded for by an alternative exon 1. The N-terminal glycine of Cα1 is myristoylated and this aliphatic chain anchors the N-terminus to an intramolecular hydrophobic pocket. Cα2 cannot be myristoylated and the crystal structure revealed that the equivalent hydrophobic pocket is unoccupied and exposed. Nuclear magnetic resonance (NMR) spectroscopy further demonstrated that detergents with hydrophobic moieties of different lengths can bind deep into this uncovered pocket. Our findings indicate that Cα2 through the hydrophobic pocket has the ability to bind intracellular targets in the sperm cell, which may modulate protein stability, activity and/or cellular localization.


    Organizational Affiliation

    Spermatech AS, N-0373 Oslo, Norway.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CAMP-DEPENDENT PROTEIN KINASE CATALYTIC SUBUNIT ALPHA 2
A, B
343Homo sapiensMutation(s): 0 
Gene Names: PRKACA (PKACA)
EC: 2.7.11.11
Find proteins for P17612 (Homo sapiens)
Go to Gene View: PRKACA
Go to UniProtKB:  P17612
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
B
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
SEP
Query on SEP
A, B
L-PEPTIDE LINKINGC3 H8 N O6 PSER
TPO
Query on TPO
A, B
L-PEPTIDE LINKINGC4 H10 N O6 PTHR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.215 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 75.776α = 90.00
b = 89.495β = 90.00
c = 114.815γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
REFMACrefinement
MOLREPphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-04-18
    Type: Initial release
  • Version 1.1: 2012-05-30
    Type: Other
  • Version 1.2: 2012-06-06
    Type: Other
  • Version 1.3: 2013-01-30
    Type: Database references, Other