European Biophysics Journal

, Volume 44, Issue 1–2, pp 17–26 | Cite as

Spectroscopic and thermodynamic properties of recombinant heat shock protein A6 from Camelus dromedarius

  • Ajamaluddin Malik
  • Abuzar Haroon
  • Haseeb Jagirdar
  • Abdulrahman M. Alsenaidy
  • Mohamed Elrobh
  • Wajahatullah Khan
  • Mohammed S. Alanazi
  • Mohammad D. Bazzi
Original Paper


Heat shock protein A6, also known as HSP70B’, is a member of the Hsp70 family of molecular chaperones. Under stressed conditions, the level of HSPA6 increases substantially, and the protein has been targeted as a biomarker of cellular stress in several studies. We report the spectroscopic and thermodynamic properties of Arabian camel species cHSPA6, determined by measurement of intrinsic and extrinsic fluorescence emission, and use of far-UV circular dichroism and dynamic multimode spectroscopy. Our results showed that cHSPA6 has similar binding affinity for both ATP and ADP (K D = ~50 nM). Binding of ATP and ADP reduced the surface hydrophobicity of the protein, and slightly altered its secondary structure, suggesting localized conformational rearrangement after ATP or ADP binding. Dynamic multimode spectroscopy revealed that cHSPA6 unfolds through three transitions with melting points (T m) of 42.3 ± 0.2, 61.3 ± 0.1, and 81.2 ± 0.2 °C. To the best of the author’s knowledge, and literature search, this is the first report of the spectroscopic and thermodynamic properties of the Arabian camel heat shock protein.


Recombinant protein Heat shock protein Protein stability Folding Fluorescence quenching Dynamic multimode spectroscopy 







Ethylenediaminetetraacetic acid






Fast protein liquid chromatography


Guanidinium hydrochloride


Isopropyl β-D-1-thiogalactopyranoside


Dissociation constant




Double strength Luria–Bertani


Nutrient broth


Molecular weight cut off


Nickel-nitrilotriacetic acid


Nucleotide binding domain


Optical density at 600 nm


Phenylmethylsulfonyl fluoride


Rotation per minute


Substrate binding domain


Terrific broth


Melting temperature



The authors extend their appreciation to King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia, for funding this work through project # A-C-11-0606.


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Copyright information

© European Biophysical Societies' Association 2014

Authors and Affiliations

  • Ajamaluddin Malik
    • 1
  • Abuzar Haroon
    • 2
  • Haseeb Jagirdar
    • 1
  • Abdulrahman M. Alsenaidy
    • 1
  • Mohamed Elrobh
    • 3
    • 5
  • Wajahatullah Khan
    • 4
  • Mohammed S. Alanazi
    • 3
  • Mohammad D. Bazzi
    • 1
    • 3
  1. 1.Protein Research Chair, Department of Biochemistry, College of ScienceKing Saud UniversityRiyadhSaudi Arabia
  2. 2.Tabuk Pharmaceuticals Manufacturing Co.DammamSaudi Arabia
  3. 3.Genome Research chair, Department of Biochemistry, College of ScienceKing Saud UniversityRiyadhSaudi Arabia
  4. 4.Department of Basic Sciences, College of Science and Health ProfessionsKing Saud Bin Abdulaziz University for Health SciencesRiyadhSaudi Arabia
  5. 5.Biochemistry Department, Faculty of ScienceAin-Shams UniversityCairoEgypt

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