The amino acid sequence of a type I copper protein with an unusual serine- and hydroxyproline-rich C-terminal domain isolated from cucumber peelings

Abstract

We have determined the amino acid sequence of a small copper protein isolated from cucumber peelings. This cupredoxin contains 137 amino acids including a pyroglutamate as the first residue. The N-terminal 110 amino acid-long domain shows 30–37% identity to 2 other cupredoxins, stellacyanin and cucumber basic blue protein. A unique feature of this protein is a 27 amino acid-long, C-terminal domain rich in 4-hydroxyproline and serine and resembling certain plant cell wall proteins. The prolines in this domain are hydroxylated to a different extent depending on the surrounding sequence.