Selectivity of Ni(II) and Zn(II) binding to Sporosarcina pasteurii UreE, a metallochaperone in the urease assembly: a calorimetric and crystallographic study
PBN-AR
Instytucja
Instytut Chemii Bioorganicznej Polskiej Akademii Nauk
Informacje podstawowe
Główny język publikacji
en
Czasopismo
Journal of Biological Inorganic Chemistry
ISSN
0949-8257
EISSN
1432-1327
Wydawca
SPRINGER
DOI
URL
Rok publikacji
2013
Numer zeszytu
8
Strony od-do
1005-1017
Numer tomu
18
Identyfikator DOI
Liczba arkuszy
Autorzy
Pozostali autorzy
+ 3
Autorzy przekładu
(liczba autorów przekładu: 0)
Słowa kluczowe
en
UreE
Nickel
Sporosarcina pasteurii
Calorimetry
Zinc
Streszczenia
Język
en
Treść
Urease is a nickel-dependent enzyme that plays a critical role in the biogeochemical nitrogen cycle by catalyzing the hydrolysis of urea to ammonia and carbamate. This enzyme, initially synthesized in the apo form, needs to be activated by incorporation of two nickel ions into the active site, a process driven by the dimeric metallochaperone UreE. Previous studies reported that this protein can bind different metal ions in vitro, beside the cognate Ni(II). This study explores the metal selectivity and affinity of UreE from Sporosarcina pasteurii (Sp, formerly known as Bacillus pasteurii) for cognate [Ni(II)] and noncognate [Zn(II)] metal ions. In particular, the thermodynamic parameters of SpUreE Ni(II) and Zn(II) binding have been determined using isothermal titration calorimetry. These experiments show that two Ni(II) ions bind to the protein dimer with positive cooperativity. The high-affinity site involves the conserved solvent-exposed His100 and the C-terminal His145, whereas the low-affinity site comprises also the C-terminal His147. Zn(II) binding to the protein, occurring in the same protein regions and with similar affinity as compared to Ni(II), causes metal-driven dimerization of the protein dimer. The crystal structure of the protein obtained in the presence of equimolar amounts of both metal ions indicates that the high-affinity metal binding site binds Ni(II) preferentially over Zn(II). The ability of the protein to select Ni(II) over Zn(II) was confirmed by competition experiments in solution as well as by analysis of X-ray anomalous dispersion data. Overall, the thermodynamics and structural parameters that modulate the metal ion specificity of the different binding sites on the protein surface of SpUreE have been established.
Cechy publikacji
ORIGINAL_ARTICLE
Inne
System-identifier
554093
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