Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: histydyna

Sortuj według:

Ogranicz wyniki do:

Polihistydylowe sekwencje z motywem His-tag – ich rola i biologiczne znaczenie oddziaływania z jonami metali

Wątły J., Kozłowski H.

Wiadomości Chemiczne

2016

[Z] 70, 11-12

1--24

His-tags are specific sequences containing six to nine subsequent histydyl residues and they are used commercially in immobilized metal affinity chromatography (IMAC) as molecular ‘anchors’ that bind to a metal ion (usually nickel), immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support [37, 38]. Consecutive histidines are the common denominator for both His-tags used in molecular biology and for quite remote biological phenomena – more than 2000 histidine- rich proteins (HRPs) are found in microorganisms including 60% and 82% of archaeal and bacterial species, respectively and their roles are not well characterized [73]. The physicochemical properties of histidine make it a versatile amino acid that influences protein conformation and enzymatic activity [15]. Many natural proteins with a His-tag domain are assigned to different functions, for example: most bacterial proteins, containing this motif are probably involved in the homeostasis of nickel ions [68, 76], while others, e.g. newly isolated peptides from the venom of the snake genus Atheris contain poly-histidyl-poly-glycyl sequences (pHpG) can act on the cardiovascular system by inhibiting snake venom metalloproteinases and affect its function by acting on specific receptors [58, 62]. His-rich motifs have been found also e.g. in Zn2+ transporters, prion proteins, His-rich glycoproteins, transcription factors or numerous copper-binding proteins [56, 67, 84]. Binding mode and the thermodynamic properties of the system depends on the specific metal ion and the histidine sequence. Despite the wide application of the His-tag for purification of proteins, little is known about the properties of metalbinding to such tag domain. Recent experimental and theoretical studies have shown that metal ions, e.g. Cu2+ can bind to various sets of imidazoles depending on the number of histidine residues that are located in His-rich sequences. The occurrence of polymorphic binding states and the formation of an α-helical structure induced by metal ion coordination suggest that proteins with a His-tag domain may serve as the dynamic site able to ‘move’ metal ions along the tag sequence [99, 100]. This might explain the frequent occurrence of such sequences in bacterial Ni2+ chaperones, which transfer the metal ion between different proteins.

The study of interactions between FAD - flavin adenine dinucleotide and histidine

Sabara D.

Zeszyty Naukowe. Chemia Spożywcza i Biotechnologia / Politechnika Łódzka

2008

Z. 72

63-71

In view of the fact that one of the amino acids, histidine, performs an important role in the interactions with flavin adenine dinucleotide (FAD) in the catalytic center of glucose oxidase (GOD), we performed an investigation if interactions between FAD and histidine. The theoretical approach indicates the stacked conformation of FAD, in which the isoalloxazine and adenine ring couple with each other, and an extended - unstacked conformation. Formation of the complex was studied using fluorescence method and computer modeling in order to define the geometrical parameters of the hydrogen bond formation by means of the semi-empirical method (AM1, PM3). The possible distances, angles and stretch vibrations were supported by fluorescence lifetime decay and the Gibbs free energy of the complex.

W pracy opisano badania oddziaływań pomiędzy dinukleotydem flawinoadeninowym a histydyną. Jeden z aminokwasów - histydyna odgrywa ważną rolę w oddziaływaniu z dinukleotydem flawinoadeninowym znajdującym się w centrum aktywnym oksydazy glukozowej (GOD). Teoria potwierdza istnienie dwóch konformacji dinukleotydu flawinoadeninowego; zamkniętej, w której pierścienie adeninowy i izoaloksazynowy reagują ze sobą oraz otwartej - liniowej. Tworzenie kompleksu pomiędzy FAD a histydyną zbadano metodami fluorescencyjnymi oraz przy użyciu optymalizacji komputerowej w celu zdefiniowania parametrów wiązania wodorowego (AM1, PM3). Określenie możliwych interakcji i konfiguracji molekuł zostało wsparte fluorescencyjnymi pomiarami czasów życia oraz wyliczeniem energii Gibbsa powstałego kompleksu.