Recent improvements in mRNA display have enabled the selection of peptides that incorporate non-natural amino acids, thus expanding chemical diversity macrocycles beyond what is accessible nature. Such libraries incorporated acids at expense natural by reassigning their codons. Here we report an alternative approach to expanded amino-acid preserves all 19 (no methionine) and adds 6 resulting hi...

We show that interactions of fatty acids with the central cavity of potassium channel KcsA can be characterized using the fluorescence probe 11-dansylaminoundecanoic acid (Dauda). The fluorescence emission spectrum of Dauda bound to KcsA in bilayers of dioleoylphosphatidylcholine contains three components, which can be attributed to KcsA-bound and lipid-bound Dauda together with unbound Dauda. ...

The membrane model previously described [Hays, T.R., Buckwalter, C.Q., Lin S.H. & Eyring, H. (1978) Proc. Natl. Acad. Sci. USA 75, 1612-1615] for ion flow through a membrane is expanded to include the effect of binding of the mobile ion at the occupiable sites in the membrane. Two different effects were investigated: alteration of the association-dissociation rates at constant equilibrium const...

The population imbalance between nuclear singlet states and triplet of strongly coupled spin-1/2 pairs, also known as order, is well protected against several common relaxation mechanisms. We study the 13C pairs in aqueous solutions 1,2-13C2 squarate over a range pH values. order accessed by introducing 18O nuclei to break chemical equivalence. dianion equilibrium with hydrogen-squarate (SqH?) ...

The binding of human plasminogen to fibrin was studied using 125Lplasminogen and uniform suspensions of noncross-linked or cross-linked human fibrin. Of the two types of plasminogen, the proteolytically modified form (NJ&-terminal lysine; Lys-plasminogen) showed a high binding affinity for both forms of fibrin, having a dissociation constant of 0.32 p~ and two binding sites per fibrin monomeric...

A graph is presented which permits facile determination of the dissociation constant constant for a macromolecule . ligand complex from gel filtration results; it can be used without a detailed understanding of the remainder of the text. When a solution of macromolecules and radioactive ligand is subjected to gel filtrations, the amount of ligand associated with the eluted macromolecule is easi...

Actin bound to the adenovirus proteinase (AVP) with a lower equilibrium dissociation constant, 4.2 nM, than those exhibited by two viral, nuclear cofactors for AVP, the 11-amino acid peptide pVIc and the viral DNA. The k(cat)/K(m) ratio for substrate hydrolysis by AVP increased 150,000-fold in the presence of actin. The 11-amino acid residue peptide corresponding to the C-terminus of actin, whi...