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Wyszukujesz frazę "substrate structure" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Recent advances in studies on biochemical and structural properties of equilibrative and concentrative nucleoside transporters
Autorzy:
Podgorska, Marzena
Kocbuch, Katarzyna
Pawelczyk, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1041310.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
nucleoside transporters
structure
gene locus
substrate specificity
tissue distribution
adenosine
Opis:
Nucleoside transporters (NT) facilitate the movement of nucleosides and nucleobases across cell membranes. NT-mediated transport is vital for the synthesis of nucleic acids in cells that lack de novo purine synthesis. Some nucleosides display biological activity and act as signalling molecules. For example, adenosine exerts a potent action on many physiological processes including vasodilatation, hormone and neurotransmitter release, platelet aggregation, and lipolysis. Therefore, carrier-mediated transport of this nucleoside plays an important role in modulating cell function, because the efficiency of the transport processes determines adenosine availability to its receptors or to metabolizing enzymes. Nucleoside transporters are also key elements in anticancer and antiviral therapy with the use of nucleoside analogues. Mammalian cells possess two major nucleoside transporter families: equilibrative (ENT) and concentrative (CNT) Na+-dependent ones. This review characterizes gene loci, substrate specificity, tissue distribution, membrane topology and structure of ENT and CNT proteins. Regulation of nucleoside transporters by various factors is also presented.
Źródło:
Acta Biochimica Polonica; 2005, 52, 4; 749-758
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The DnaK chaperones from the archaeon Methanosarcina mazei and the bacterium Escherichia coli have different substrate specificities
Autorzy:
Żmijewski, Michal
Skórko-Glonek, Joanna
Tanfani, Fabio
Banecki, Bogdan
Kotlarz, Agnieszka
Macario, Alberto
Lipińska, Barbara
Powiązania:
https://bibliotekanauki.pl/articles/1040934.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
archaeal DnaK quaternary structure
archaeal Hsp70(DnaK)
substrate-binding by archaeal DnaK
Opis:
Hsp70 (DnaK) is a highly conserved molecular chaperone present in bacteria, eukaryotes, and some archaea. In a previous work we demonstrated that DnaK from the archaeon Methanosarcina mazei (DnaKMm) and the DnaK from the bacterium Escherichia coli (DnaKEc) were functionally similar when assayed in vitro but DnaKMm failed to substitute for DnaKEc in vivo. Searching for the molecular basis of the observed DnaK species specificity we compared substrate binding by DnaKMm and DnaKEc. DnaKMm showed a lower affinity for the model peptide (a-CALLQSRLLS) compared to DnaKEc. Furthermore, it was unable to negatively regulate the E. coli σ32 transcription factor level under heat shock conditions and poorly bound purified σ32, which is a native substrate of DnaKEc. These observations taken together indicate differences in substrate specificity of archaeal and bacterial DnaKs. Structural modeling of DnaKMm showed some structural differences in the substrate-binding domains of DnaKMm and DnaKEc, which may be responsible, at least partially, for the differences in peptide binding. Size-exclusion chromatography and native gel electrophoresis revealed that DnaKMm was found preferably in high molecular mass oligomeric forms, contrary to DnaKEc. Oligomers of DnaKMm could be dissociated in the presence of ATP and a substrate (peptide) but not ADP, which may suggest that monomer is the active form of DnaKMm.
Źródło:
Acta Biochimica Polonica; 2007, 54, 3; 509-522
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conserved Cys residue influences catalytic properties of potato endo-(1→3)-β-glucanase GLUB20-2
Autorzy:
Witek, Agnieszka
Witek, Kamil
Hennig, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1040688.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
GLUB20-2
inhibition
endo-(1→3)-β-glucanase
Solanum tuberosum
structure-function relationships
substrate specificity
Opis:
The synthesis and degradation of (1→3)-β-glycosidic bonds between glucose moieties are essential metabolic processes in plant cell architecture and function. We have found that a unique, conserved cysteine residue, positioned outside the catalytic centre of potato endo-(1→3)-β-glucanase - product of the gluB20-2 gene, participates in determining the substrate specificity of the enzyme. The same residue is largely responsible for endo-(1→3)-β-glucanase inhibition by mercury ions. Our results confirm that the spatial adjustment between an enzyme and its substrate is one of the essential factors contributing to the specificity and accuracy of enzymatic reactions.
Źródło:
Acta Biochimica Polonica; 2008, 55, 4; 791-797
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural basis of the interspecies interaction between the chaperone DnaK(Hsp70) and the co-chaperone GrpE of archaea and bacteria
Autorzy:
Żmijewski, Michał
Skórko-Glonek, Joanna
Tanfani, Fabio
Banecki, Bogdan
Kotlarz, Agnieszka
Macario, Alberto
Lipińska, Barbara
Powiązania:
https://bibliotekanauki.pl/articles/1041069.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
substrate-binding domain
DnaK-GrpE complex
archaeal Hsp70(DnaK)
archaeal DnaK structure
molecular chaperones
ATPase domain
Opis:
Hsp70s are chaperone proteins that are conserved in evolution and present in all prokaryotic and eukaryotic organisms. In the archaea, which form a distinct kingdom, the Hsp70 chaperones have been found in some species only, including Methanosarcina mazei. Both the bacterial and archaeal Hsp70(DnaK) chaperones cooperate with a GrpE co-chaperone which stimulates the ATPase activity of the DnaK protein. It is currently believed that the archaeal Hsp70 system was obtained by the lateral transfer of chaperone genes from bacteria. Our previous finding that the DnaK and GrpE proteins of M. mazei can functionally cooperate with the Escherichia coli GrpE and DnaK supported this hypothesis. However, the cooperation was surprising, considering the very low identity of the GrpE proteins (26%) and the relatively low identity of the DnaK proteins (56%). The aim of this work was to investigate the molecular basis of the observed interspecies chaperone interaction. Infrared resolution-enhanced spectra of the M. mazei and E. coli DnaK proteins were almost identical, indicating high similarity of their secondary structures, however, some small differences in band position and in the intensity of amide I' band components were observed and discussed. Profiles of thermal denaturation of both proteins were similar, although they indicated a higher thermostability of the M. mazei DnaK compared to the E. coli DnaK. Electrophoresis under non-denaturing conditions demonstrated that purified DnaK and GrpE of E. coli and M. mazei formed mixed complexes. Protein modeling revealed high similarity of the 3-dimensional structures of the archaeal and bacterial DnaK and GrpE proteins.
Źródło:
Acta Biochimica Polonica; 2007, 54, 2; 245-252
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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