title: Effects of Group 3 LEA protein model peptides on desiccation-induced protein aggregation.
abstract: Group 3 late embryogenesis abundant (G3LEA) proteins have amino acid sequences with characteristic 11-mer motifs and are known to reduce aggregation of proteins during dehydration. Previously, we clarified the structural and thermodynamic properties of the 11-mer repeating units in G3LEA proteins using synthetic peptides composed of two or four tandem repeats originating from an insect (Polypedilum vanderplanki), nematodes and plants. The purpose of the present study is to test the utility of such 22-mer peptides as protective reagents for aggregation-prone proteins. For lysozyme, desiccation-induced aggregation was abrogated by low molar ratios of a 22-mer peptide, PvLEA-22, derived from a P. vanderplanki G3LEA protein sequence. However, an unexpected behavior was noted for the milk protein, α-casein. On drying, the resultant aggregation was significantly suppressed in the presence of PvLEA-22 with its molar ratios>25 relative to α-casein. However, when the molar ratio was <10, aggregation occurred on addition of PvLEA-22 to aqueous solutions of α-casein. Other peptides derived from nematode, plant and randomized G3LEA protein sequences gave similar results. Such an anomalous solubility change in α-casein was shown to be due to a pH shift to ca. 4, a value nearly equal to the isoelectric point (pI) of α-casein, when any of the 22-mer peptides was mixed. These results demonstrate that synthetic peptides derived from G3LEA protein sequences can reduce protein aggregation caused both by desiccation and, at high molar ratios, also by pH effects, and therefore have potential as stabilization reagents.
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Furuki
authors.forename: Tempei
authors.initials: T
authors.lastname: Shimizu
authors.forename: Sohini
authors.initials: S
authors.lastname: Chakrabortee
authors.forename: Kentarou
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Rie
authors.initials: R
authors.lastname: Hatanaka
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takahashi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kikawada
authors.forename: Takashi
authors.initials: T
authors.lastname: Okuda
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Mihara
authors.forename: Alan
authors.initials: A
authors.lastname: Tunnacliffe
authors.forename: Minoru
authors.initials: M
authors.lastname: Sakurai
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry*; D002364:Caseins / Q000737:chemistry*; D011232:Chemical Precipitation; D002683:Chironomidae / Q000737:chemistry; D042621:Comamonadaceae / Q000737:chemistry; D003890:Desiccation; D015801:Helminth Proteins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019476:Insect Proteins / Q000737:chemistry*; D007700:Kinetics; D009113:Muramidase / Q000737:chemistry*; D009348:Nematoda / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis*; D010940:Plant Proteins / Q000737:chemistry*; D010944:Plants / Q000737:chemistry; D017433:Protein Structure, Secondary; D060327:Solid-Phase Synthesis Techniques; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D002364:Caseins; D015801:Helminth Proteins; D019476:Insect Proteins; D010455:Peptides; D010940:Plant Proteins; D009113:Muramidase