Prediction of the plant beta-barrel proteome: a case study of the chloroplast outer envelope.
In the postgenomic era, the transformation of genetic information into biochemical meaning is required. We have analyzed the proteome of the chloroplast outer envelope membrane by an in silico and a proteomic approach. Based on its evolutionary relation to the outer membrane of Gram-negative bacteria, the outer envelope membrane should contain a large number of beta-barrel proteins. We therefore calculated the probability for the existence of beta-sheet, beta-barrel, and hairpin structures among all proteins of the Arabidopsis thaliana genome. According to the existence of these structures, a number of candidates were selected. This protein pool was analyzed by TargetP to discard sequences with signals that would direct the protein to other organelles different from chloroplasts. In addition, the pool was manually controlled for the presence of proteins known to function outside of the chloroplast envelope. The approach developed here can be used to predict the topology of beta-barrel proteins. For the proteomic approach, proteins of highly purified outer envelope membranes of chloroplasts from Pisum sativum were analyzed by ESI-MS/MS mass spectrometry. In addition to the known components, four new proteins of the outer envelope membranes were identified in this study.
Schleiff
Enrico
E
Botanisches Institut der Ludwig-Maximilian Universität München, 80368 München, Germany. schleiff@botanik.biologie.uni-muenchen.de
Eichacker
Lutz Andreas
LA
Eckart
Kerstin
K
Becker
Thomas
T
Mirus
Oliver
O
Stahl
Tanja
T
Soll
Jürgen
J
D000465:Algorithms; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000737:chemistry / Q000502:physiology; D002736:Chloroplasts / Q000737:chemistry / Q000502:physiology*; D019295:Computational Biology; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D020543:Proteome
D020543:Proteome