Maize Homolog Research Articles

Characterization of the wheat mitochondrial orf25 gene

The wheat mitochondrial orf25 nucleotide sequence of 576 bp has been determined. Its derived protein sequence shares 88% and 75% amino acid identity with those of maize and tobacco mitochondria, respectively. The wheat and tobacco orf25 sequences lack four inserts, of 6 bp to 36 bp, that are present in the maize homologue. The wheat orf25 gene is actively transcribed and is preceded by a regulatory sequence block very similar to those located upstream of the wheat coxII and atp6 genes. Our observations support the view that orf25 sequences encode a functional polypeptide in plant mitochondria.

Distribution, purification and N-terminal amino acid sequence of sorghum reduced-soluble protein

Reduced-soluble protein (RSP), a protein soluble in water and aqueous alcohol plus reducing agent comprising a very high proportion of proline and high levels of cysteine and histidine, has been found in two widely differing types of sorghum in addition to the cultivar from which it was first isolated. There was no difference in the mobility of the RSPs from the three cultivars when subjected to either sodium dodecyl sulphate- or non-ionic detergent urea-polyacrylamide gel electrophoresis. However, sorghum RSP had slightly higher electrophoretic mobility than its maize homologue using the latter technique. Some purification of sorghum RSP was achieved by phosphocellulose chromatography, although a very low yield was obtained owing to interaction between the protein and the phosphocellulose resin. Isoelectric focusing of the chromatographic fractions resolved sorghum RSP into two main and several minor bands, most of which were more basic than the total kafirin bands. The N-terminal primary structure of the heterogeneous sorghum RSP showed no polymorphism, and ten of the first 11 residues were identical with the corresponding sequence of maize RSP. The sorghum homologue also appeared to contain the repeating hexapeptide Pro-Pro-Pro-Val-His-Leu found in maize RSP.