title: Structural stability of adenylate kinase from the sulfate-reducing bacteria Desulfovibrio gigas.
abstract: A novel adenylate kinase (AK) has recently been purified from Desulfovibrio gigas and characterized as a Co(2+)/Zn(2+)-containing enzyme: this is an unusual characteristic for AKs from Gram-negative bacteria, in which these enzymes are normally devoid of metals. Here, we studied the conformational stability of holo- and apo-AK as a function of temperature by differential scanning calorimetry (DSC), circular dichroism (CD), and intrinsic fluorescence spectroscopy. The thermal unfolding of AK is a cooperative two-state process, and is sufficiently reversible in the 9-11 pH range, that can be correctly interpreted in terms of a simple two-state thermodynamic model. The spectral parameters as monitored by ellipticity changes in the CD spectra of the enzyme as well as the decrease in tryptophan intensity emission upon heating were seen to be good complements to the highly sensitive but integral DSC-method.
authors.affiliation: Departamento de Química, Centro de Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Olga Yu
authors.initials: OY
authors.lastname: Gavel
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Bursakov
authors.forename: David G
authors.initials: DG
authors.lastname: Pina
authors.forename: Galina G
authors.initials: GG
authors.lastname: Zhadan
authors.forename: José J G
authors.initials: JJ
authors.lastname: Moura
authors.forename: Isabel
authors.initials: I
authors.lastname: Moura
authors.forename: Valery L
authors.initials: VL
authors.lastname: Shnyrov
mesh_terms: D000263:Adenylate Kinase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D045286:Desulfovibrio gigas / Q000201:enzymology*; D004795:Enzyme Stability; D011487:Protein Conformation; D011489:Protein Denaturation; D013050:Spectrometry, Fluorescence; D016999:Sulfur-Reducing Bacteria / Q000201:enzymology*; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry
chemical_list: D014364:Tryptophan; D000263:Adenylate Kinase