Inhibition of oligo(glutamine) precipitation by glutamine-containing peptides.
When a solution of glutamine is added to solid 1,1'-carbonyldiimidazole, a mixture of oligo(glutamine)s up to about the 11-mer is formed rapidly. On standing overnight, the solution deposits a precipitate that does not easily redissolve. We have studied the inhibition of this precipitation by glutamine-containing peptides. We find that the alternating peptides (arg.gln)(4) and (arg.gln)(8) are efficient inhibitors of precipitation while arg(5), (glu.gln)(4), and a nonalternating octapeptide of the same composition as (arg.gln)(4) do not inhibit precipitation even though all the arg-containing peptides readily adsorb to oligo(glutamine) precipitates. A possible structural basis for this difference is discussed.
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The Salk Institute for Biological Studies, San Diego, California 92186-5800, USA.
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D000327:Adsorption; D011232:Chemical Precipitation; D005973:Glutamine / Q000737:chemistry*; D007093:Imidazoles; D066298:In Vitro Techniques; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification; D012996:Solutions; D013439:Sulfhydryl Reagents
D007093:Imidazoles; D009842:Oligopeptides; D010455:Peptides; D012996:Solutions; D013439:Sulfhydryl Reagents; D005973:Glutamine; C097188:polyglutamine; C006900:N,N-carbonyldiimidazole