title: Amino acid substitutions around the chromophore of the chromoprotein Rtms5 influence polypeptide cleavage.
abstract: Extension of the conjugated pi-system of many all-protein chromophores with an acylimine bond is the basis for their red-shifted optical properties. The presence of this post-translational modification is evident in crystal structures of these proteins. Harsh denaturation of proteins containing an acylimine bond results in partial polypeptide cleavage. For the red fluorescent protein DsRed, the extent of cleavage is quantitative. However, this is not the case for the blue non-fluorescent chromoprotein Rtms5, even though all chromophores in tetrameric Rtms5 contain an acylimine bond. We have identified two positions around the chromophore of Rtms5 where substitutions can promote or suppress the extent of cleavage on harsh denaturation. We propose a model in which cleavage of Rtms5 is facilitated by a trans to cis isomerisation of the chromophore.
authors.affiliation: The Protein Crystallography Unit, Monash Centre for Synchrotron Science, Monash University, Clayton Campus, Vic. 3800, Australia.
authors.forename: Kristina
authors.initials: K
authors.lastname: Turcic
authors.forename: Anne
authors.initials: A
authors.lastname: Pettikiriarachchi
authors.forename: Jion
authors.initials: J
authors.lastname: Battad
authors.forename: Pascal G
authors.initials: PG
authors.lastname: Wilmann
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
authors.forename: Sophie G
authors.initials: SG
authors.lastname: Dove
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Devenish
authors.forename: Mark
authors.initials: M
authors.lastname: Prescott
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D003198:Computer Simulation; D008164:Luminescent Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D008164:Luminescent Proteins; D010455:Peptides