title: Evidence for an unprecedented histidine hydroxyl modification on D2-His336 in Photosystem II of Thermosynechoccocus vulcanus and Thermosynechoccocus elongatus.
abstract: The electron density map of the 3D crystal of Photosystem II from Thermosynechococcus vulcanus with a 1.9 Å resolution (PDB: 3ARC ) exhibits, in the two monomers in the asymmetric unit cell, an, until now, unidentified and uninterpreted strong difference in electron density centered at a distance of around 1.5 Å from the nitrogen Nδ of the imidazole ring of D2-His336. By MALDI-TOF/MS upon tryptic digestion, it is shown that ~20-30% of the fragments containing the D2-His336 residue of Photosystem II from both Thermosynechococcus vulcanus and Thermosynechococcus elongatus bear an extra mass of +16 Da. Such an extra mass likely corresponds to an unprecedented post-translational or chemical hydroxyl modification of histidine.
authors: Proteo-Science Research Center, Ehime University , Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
authors: Miwa
authors: M
authors: Sugiura
authors: Kazumi
authors: K
authors: Koyama
authors: Yasufumi
authors: Y
authors: Umena
authors: Keisuke
authors: K
authors: Kawakami
authors: Jian-Ren
authors: JR
authors: Shen
authors: Nobuo
authors: N
authors: Kamiya
authors: Alain
authors: A
authors: Boussac
mesh_terms: D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D000458:Cyanobacteria / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017665:Hydroxyl Radical / Q000378:metabolism*; D008958:Models, Molecular; D008970:Molecular Weight; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D045332:Photosystem II Protein Complex; D017665:Hydroxyl Radical; D006639:Histidine