Avtor/Urednik		Bavec, Aljoša
Naslov		Interakcije amfipatičnih peptidov z G-proteini
Prevedeni naslov		Effect of amphipathic peptides on G-proteins
Tip		monografija
Kraj izdaje		Ljubljana
Založnik		Medicinska fakulteta
Leto izdaje		1998
Obseg		str. 66
Jezik		slo
Abstrakt		Eight different amphipathic peptides were tested as modulators of GTPase activity of G-proteins from rat braincortex membranes: mastoparan and melittin (components of wasp and bee venom, respectively), MAS17 (inactive mastoparan analog LNGFR (272-291) and LNGFR (370-383) (peptides derived fromnerve growth factor receptor), PD1 (synthetic peptitergent), beta-amyloid protein (25-35) (peptide derived from beta-amyloid protein) and cys-pAntp (43-58) (homeodomain part of Drosophila antennapedia protein). Four of the peptides (mastoparan, melittin, PD1 and beta-amyloid protein (25-35) increased GTPase activity, other peptides showed no effect. Correlationof these data with peptide sequences, their predicted secondary structure and residue solvent accessibility pointed to two types of activators. First type (melittin and PD1) is characterised by longer (24-26 amino acids) almost fully amphipathic helical structure with separated charges at both ends of the sequence. Second type of activators (mastoparan and beta-amyloid protein (25-35)) is a shorter helix (11-14 amino acids) and contains a motif consisted of lysine in position 4, followed by 5 to 6 amino acids with the residues of low solvent accessibility. The GTPase activity of G-proteins from rat brin corctial membranes by peptitergent PD1 was investigated in more detail. PD1 increased the GTPase activity of G-proteins in a dose dependent manner to a maximal level 2-fold higher than the basel. This dependence was characterised with values of EC50 = 3,5 +- 1,2 micro M; and Hill coefficient nH = 2,1 +- 0,3. In the presence of 3 micro M PD1, both Km and Vmax for the hydrolysis of GTP increased to levels 3,5- and 2,0-fold basal, respectively; the rate of (35S)GTP gama S binding was also increased to level, 2,45-fold basal.(Abstract truncated at 2000 characters)
Deskriptorji		CEREBRAL CORTEX G-PROTEINS GTP PHOSPHOHYDROLASE CELL MEMBRANE RATS BEE VENOMS WASP VENOMS PERTUSSIS TOXINS BINDING, COMPETITIVE