The Ycf54 protein is part of the membrane component of Mg‐protoporphyrin IX monomethyl ester cyclase from barley (Hordeum vulgareL.)

• Published in: The FEBS journal Vol. 281; no. 10; pp. 2377 - 2386
• Main Authors: Bollivar, David, Braumann, Ilka, Berendt, Kasper, Gough, Simon P., Hansson, Mats
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.05.2014
• Subjects: Barley; Biosynthesis; chlorophyll; cyclase; Enzymes; etioplast; Genes, Plant; Hordeum - genetics; Hordeum - metabolism; isocyclic ring; Membranes; Mg‐protoporphyrin monomethyl ester; Mutation; Oxygenases - chemistry; Oxygenases - genetics; Oxygenases - metabolism; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plastids - metabolism; Proteins; Protoporphyrins - metabolism; Mg-protoporphyrin monomethyl ester; chlorophyll; cyclase; etioplast; isocyclic ring
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/febs.12790

The biosynthesis of chlorophyll has been demonstrated to require an extensive set of enzymes, the initial stages of which are shared with the synthesis of heme. Of these enzymes, the most enigmatic is the Mg‐protoporphyrin IX monomethyl ester cyclase (EC 1.14.13.81). This enzyme requires components found associated with the plastid membrane and the plastid soluble fraction. One of the components, XanL, is found associated with the membrane and another protein, Ycf54, has recently been identified based upon association with XanL. This study describes a deeper analysis of the role of Ycf54 in the enzyme and the localization of the protein in barley plastids. The results clearly demonstrate a strong association of Ycf54 with XanL, absence of Ycf54 from soluble fractions necessary for activity and more evidence for a third membrane localized component of the enzyme. Structured digital Ycf54 and Ycf54 bind by molecular sieving (1, 2) The enzyme Mg‐protoporphyrin IX monomethyl ester cyclase (EC 1.14.13.81) plays a central role in the biosynthesis of chlorophyll. The protein Ycf54 was recently identified as part of the enzyme, and is associated with the plastid membrane associated subunit XanL. This work describes an analysis of the role of Ycf54 in the enzyme. It also demonstrates additional soluble factors remain unidentified.