Figure 4.

GvP1 shows characteristics of typical, dicotyledon extensins. A) Partial sequence of GvP1 deduced from its 5' truncated cDNA. Sequences obtained by Edman sequencing of isolated GvP1 peptides P4 (dashed line) and P6 (solid line) are indicated. CNBr cleavage sites are indicated by arrows. B) MALDI-TOF MS of Peptide 6 demonstrates mass heterogeneity due to variable arabinosylation (periodicity of 132 Da) and hydroxylation of proline residues (periodicity of 16 Da). The differing ion species are labelled along the x-axis with: [mass] number of Ara, number of Hyp (its identity as a homoserine (HS) or homolactone serine (HL) cleavage product).