August H. Maki

Learn More
The interaction of the enzyme Escherichia coli RI methyl transferase (methylase) with an arsenic(III) derivative of cacodylic acid has been investigated by optical detection of triplet-state magnetic resonance (ODMR) spectroscopy in zero applied magnetic field. The reactive derivative (CH3)2AsSR is formed by the reduction of cacodylate by a thiol. The(More)
The phosphorescence and zero field optically detected magnetic resonance (ODMR) of the tryptophan (Trp) residues of alkaline phosphatase from Escherechia coli are examined. Each Trp is resolved optically and identified with the aid of the W220Y mutant and the terbium complex of the apoenzyme. Trp(109), known from earlier work to be the source of(More)
Phosphorescence and optically detected magnetic resonance (ODMR) measurements are reported on four single-tryptophan mutants of lac repressor protein from Escherichia coli: H74W/Wless, W201Y, Y273W/Wless, and F293W/Wless, where Wless represents a protein background containing the double mutation W201Y/W220Y. The single-tryptophan residues are located in the(More)
Time-resolved and steady-state fluorescence, low-temperature phosphorescence, and optically detected magnetic resonance (ODMR) measurements have been made to resolve the luminescence contributions of the two intrinsic tryptophan residues in the subunits of trp aporepressor from Escherichia coli. Assignments of spectral information have been confirmed by use(More)
Binding of CH3Hg(II) to duplex and single-stranded calf thymus DNA leads to an external heavy atom effect that is associated with the formation of complexes directly with the purine and pyrimidine bases. When CH3Hg(II) is added at a concentration insufficient to cause denaturation, clearly distinguishable optical detection of magnetic resonance spectra are(More)
Room temperature fluorescence and low-temperature phosphorescence studies of the association of p10, a basic low molecular weight single-stranded DNA binding protein isolated from murine leukemia viruses, point to the involvement of its single tryptophan residue in a close-range interaction with single-stranded polynucleotides. Optically detected(More)
The mammalian heterogeneous ribonucleoprotein (hnRNP) A1 and its constituent N-terminal domain, termed UP1, have been studied by steady-state and dynamic fluorimetry, as well as phosphorescence and optically detected magnetic resonance (ODMR) spectroscopy at cryogenic temperatures. The results of these diverse techniques coincide in assigning the site of(More)
Phosphorescence and optically detected magnetic resonance (ODMR) spectra of tryptophan (W) and several of its analogues (4-, 5-, 6-methyltryptophan (MeW); 4-, 5-, 6-fluorotryptophan (FW); 5-bromotryptophan) are compared with those of complexes formed with the W-free trp aporepressor from Escherichia coli (W19,99F). W19,99F binds W and each analogue except(More)
Spectroscopic studies have been performed to characterize the solution structure of the V66W mutant of Staphylococcal nuclease and the corresponding 1-136 fragment, referred to as V66W'. Whereas wild-type nuclease has a single tryptophan residue at position 140, the V66W mutant has a second tryptophan residue at position 66, which is the only such residue(More)
Fluorescence and optical detection of triplet state magnetic resonance (ODMR) spectroscopy have been employed to study the complexes formed between single-stranded polynucleotides and Escherichia coli ssb gene products (SSB) in which tryptophans 40, 54, and 88 are selectively, one residue at a time, replaced by phenylalanine using site-specific(More)