Structural diversity in the small heat shock protein superfamily: control of aggregation by the N-terminal region.
The small heat shock protein superfamily, extending over all kingdoms, is characterized by a common core domain with variable N- and C-terminal extensions. The relatively hydrophobic N-terminus plays a critical role in promoting and controlling high-order aggregation, accounting for the high degree of structural variability within the superfamily. The effects of N-terminal volume on aggregation were studied using chimeric and truncated proteins. Proteins lacking the N-terminal region did not aggregate above the tetramers, whereas larger N-termini resulted in large aggregates, consistent with the N-termini packing inside the aggregates. Variation in an extended internal loop differentiates typical prokaryotic and plant superfamily members from their animal counterparts; this implies different geometry in the dimeric building block of high-order aggregates.
Salerno
John C
JC
Center for Biophysics and Department of Biology, Rensselaer Polytechnic Institute, Science Center, Troy, NY 12180-3590, USA. salerj@rpi.edu
Eifert
Cheryl L
CL
Salerno
Kathleen M
KM
Koretz
Jane F
JF
D000595:Amino Acid Sequence; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D038201:alpha-Crystallins / Q000737:chemistry
D006360:Heat-Shock Proteins; D011994:Recombinant Proteins; D038201:alpha-Crystallins