Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly 2  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 80.24 kDa 
• Atom Count: 5801 
• Modelled Residue Count: 648 
• Deposited Residue Count: 686 
• Unique protein chains: 1

4AE9

Structure and function of the Human Sperm-Specific Isoform of Protein Kinase A (PKA) Catalytic Subunit C alpha 2

• DOI: 10.2210/pdb4AE9/pdb

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21
• Mutation(s): No 


• Deposited: 2012-01-09 Released: 2012-04-18 
• Deposition Author(s): Hereng, T.H., Backe, P.H., Kahmann, J., Scheich, C., Bjoras, M., Skalhegg, B.S., Rosendal, K.R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.264 
• R-Value Work: 0.198 
• R-Value Observed: 0.201 

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

• PubMed: 22504716 
• DOI: 10.1016/j.jsb.2012.03.013
• Primary Citation of Related Structures:  
  4AE6, 4AE9


• 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-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.

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Organizational Affiliation: 

Spermatech AS, N-0373 Oslo, Norway.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CAMP-DEPENDENT PROTEIN KINASE CATALYTIC SUBUNIT ALPHA	A, B	343	Homo sapiens	Mutation(s): 0  Gene Names: PRKACA, PKACA EC: 2.7.11.11
Find proteins for P17612 (Homo sapiens) Explore P17612  Go to UniProtKB:  P17612
NIH Common Fund Data Resources
PHAROS:  P17612 GTEx:  ENSG00000072062

Small Molecules

Modified Residues  2 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SEP	A, B	L-PEPTIDE LINKING	C3 H8 N O6 P		SER
TPO	A, B	L-PEPTIDE LINKING	C4 H10 N O6 P		THR

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.264 
• R-Value Work: 0.198 
• R-Value Observed: 0.201 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 76.396	α = 90
b = 89.971	β = 90
c = 115.68	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
MOSFLM	data reduction
SCALEPACK	data scaling
MOLREP	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2012-01-09 
• Released Date: 2012-04-18 
Deposition Author(s): Hereng, T.H., Backe, P.H., Kahmann, J., Scheich, C., Bjoras, M., Skalhegg, B.S., Rosendal, K.R.

Revision History  

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