The major peptidyl-prolyl isomerase activity in thylakoid lumen of plant chloroplasts belongs to a novel cyclophilin TLP20.
Fractionation of proteins from the thylakoid lumen of spinach chloroplasts combined with peptidyl-prolyl cis/trans isomerase (PPIase) measurements revealed a major isomerase activity that was ascribed to a novel enzyme TLP20 (thylakoid lumen PPIase of 20 kDa). TLP20 was inhibited by cyclosporin A and mass spectrometric sequencing of tryptic peptides confirmed its classification as a cyclophilin. Genes encoding similar putative thylakoid cyclophilins with a unique insert of three amino acids NPV in their N-termini were found in chromosome 5 of both Arabidopsis and rice. TLP20 is suggested to be the major PPIase and protein folding catalyst in the thylakoid lumen of plant chloroplasts.
Division of Cell Biology, Linköping University, SE-581 85 Linköping, Sweden.
Anna
A
Edvardsson
Said
S
Eshaghi
Alexander V
AV
Vener
Bertil
B
Andersson
D000595:Amino Acid Sequence; D021983:Cyclophilins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D018724:Spinacia oleracea / Q000201:enzymology; D020524:Thylakoids / Q000201:enzymology*
D021983:Cyclophilins