Third, 60 base pairs downstream from this FLRFamide, the cDNA encodes the tetrabasic cleavage site (Arg-Lys-Arg-Arg; RKRR) reported previously (Lutz et al., 1992).
Finally, 111 base pairs downstream, about 3/5 of the distance between the tetrabasic (RKRR) site and the first copy of FMRFamide, the cDNA encodes a dibasic cleavage site (KR).
In particular, the Cepaea precursor also encodes two copies of pQFYRFamide, a copy of FLRFamide, a tetrabasic site, and a dibasic cleavage site.
The 5[prime] end of the sequence encodes a copy of FLRFamide, the tetrabasic site, and the dibasic cleavage site.
aspersa, three off-setting gaps were required to align the tetrabasic and dibasic cleavage sites in the two species.
First, the C-terminal end of the precursor (always downstream of the tetrabasic sequence, RKRR) is the site of repeated segments, each comprising a FMRF sequence with its processing signals and acidic spacers.
The functional significance of the tetrabasic site and the sequences surrounding it has been considered from time to time (reviewed by Linacre et al., 1990).
Our previous experiment indicated that feeding pharmacological tetrabasic zinc chloride (TBZC) improved growth performance of weanling piglets (Zhang and Guo, 2007).
TBZC = Tetrabasic zinc chloride; ADG = Average daily growth; ADFI = Average daily feed intake; FCR = Feed conversion ratio; Control = Control diet; TZn = Supplemented with 2,000 mg Zn from TBZC/kg; Pair-fed = Pair-fed with respect to the control diet.