Pear (Pyrus pyrifolia L.) has an S-RNase-based gametophytic self-incompatibility (SI) mechanism, and S-RNase has also been implicated in the rejection of self-pollen and genetically identical pollen. However, RNA degradation might be only the beginning of the SI response, not the end. Recent in vitro studies suggest that S-RNase triggers mitochondrial alteration and DNA degradation in the incom...

The style component of the self-incompatibility (S) locus of the wild tomato Lycopersicon peruvianum (L.) Mill. is an allelic series of glycoproteins with ribonuclease activity (S-RNases). Treatment of the S,-RNase from L . peruvianum with iodoacetate at p H 6.1 led to a loss of RNase activity. In the presence of a competitive inhibitor, guanosine 3”Ionophosphate (3‘-CMP), the rate of RNase ina...

RNase-related proteins (RRPs) are S- and S-like RNase homologs lacking the active site required for RNase activity. Here we describe the cloning and characterization of the rice (Oryza sativa) RRP gene (OsRRP). A single copy of OsRRP occurs in the rice genome. OsRRP contains three introns and an open reading frame encoding 252 amino acids, with the replacement of two histidines involved in the ...

A protected linear polypeptide of 124 amino acid residues with the sequence of bovine pancreatic ribonuclease A was synthesized by the solid phase method. The polypeptide was removed from the solid support and pursed, and the four disulfide bonds were closed by air oxidation of the reduced form. The synthetic enzyme was fractionated by gel filtration and ion exchange chromatography, and the mat...

Local and Long-Range Electrostatic Interactions in Denatured Ribonuclease Sa: Comparing the Denatured Protein with Model Peptides (April 2002) Michael Douglas Daily Department of Biochemistry and Biophysics Texas A&M University Fellows Advisor: Dr. J. Martin Scholtz Department of Biochemistry and Biophysics The folding ol'proteins into three-dimensional, biologically active conformations demand...

In self-incompatible (SI) plants, the S locus acts to prevent growth of self-pollen and thus promotes outcrossing within the species. Interspecific crosses between SI and self-compatible (SC) species often show unilateral incompatibility that follows the SI x SC rule: SI species reject pollen from SC species, but the reciprocal crosses are usually compatible. The general validity of the SI x SC...