Heteropolypeptides from poly-alpha-cyanoglycine and hydrogen cyanide: a model for the origin of proteins

Poly-alpha-cyanoglycine, a homopolymer synthesized from the N-carboxyanhydride of alpha-cyanoglycine, is converted by cumulative reaction of hydrogen cyanide to heteropolypeptides that can be hydrolyzed to protein amino acids, including glycine, alanine, valine, aspartic acid, and glutamic acid. These results are consistent with the hypothesis that the original heteropolypeptides on the earth arose spontaneously from hydrogen cyanide and water without the intervening formation of alpha-amino acids.

Reciprocal inhibition of mouse leukemia virus infection by Fv-1 allele cell extracts

Soluble extracts of mouse cells with Fv-1(n) or Fv-1(b) gene alleles specifically and reciprocally inhibit infection of B- or N-tropic mouse leukemia viruses in permissive cell cultures. NB-tropic virus infection was not inhibited by either cell extract. Extracts from Fv-1(-) cells did not inhibit infection by the three virus host-range types, but N- or B-tropic virus infection of Fv-1(-) cells was inhibited by extracts of the nonpermissive cells, and Fv-1(nb) cell extracts inhibited both viruses. The maximum degree of inhibition was 50-80% as determined by immunofluorescent or plaque assays, with extracts containing up to 500 mug/ml of nonpermissive cell protein. The inhibitor(s) is relatively unstable since activity is lost after 2 hr at 37 degrees or 30 min at 56 degrees . The inhibitor(s) was most effective if added 2 hr before or within 2 hr after infection, did not react with the virus directly, inhibit virus attachment, or inhibit the normal cell functions tested. These results indicate that nonpermissive mouse cells contain a product, possibly determined by the Fv-1 gene, which inhibits some early postpenetration event(s) in leukemia virus infection.

The redox potentials of the two-iron plant and algal ferredoxins. An electrostatic model

The two-iron-sulphur co-ordination centre in plant and algal ferredoxins is considered as a collection of charged ions whose net negative charge is twice that of the one-iron-sulphur protein rubredoxin. Calculation of the electrostatic free-energy changes for reduction of the two types of proteins indicates that the redox potential of the two-iron-sulphur proteins should be more negative than that of the one-iron-sulphur protein and that in biological systems the ferredoxins should function as one-electron transfer proteins.