Richard A. Alden

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The structure of ferricytochrome cz from the non-sulfur purple photosynthetic bacterium Rhodospirillum rubrum has been determined at 2 A resolution by x-ray crystallographic methods. The 112-residue polypeptide chain encloses a single covalently bound heme in a predominantly hydrophobic environment, leaving only one edge exposed to the solvent at the front(More)
A central eight-stranded beta-pleated sheet is the main feature of the polypeptide backbone folding in dihydrofolate reductase. The innermost four strands and two bridging helices are geometrically similar to but are connected in a different way from those in the dinucleotide binding domains found in nicotinamide-adenine dinucleotide-linked dehydrogenases.(More)
The structure of Chromatium high potential iron protein (HiPIP) has been refined by semiautomatic Fo-Fc (observed minus calculated structure amplitude Fourier methods to a convential R index, R=sum of the absolute value of Fo-Fc divided by the sum of Fo, of 24.7% for a model in which bond distances and angles are constrained to standard values. Bond length(More)
The three-dimensional conformation of yeast cytochrome c peroxidase has been determined from a 2.5 A electron density map computed with phases obtained from two isomorphous mercury derivatives. Partial sequence information that has recently become available aided in completion of the tracing of the polypeptide backbone, confirmed the presence of a proximal(More)
1. A detailed study of cytochrome C oxidse activity with Keilin-Hartree particles and purified beef heart enzyme, at low ionic strength and low cytochrome C concentrations, showed biphasic kinetics with apparent Km1 = 5 x 10(-8) M, and apparent Km2 = 0.35 to 1.0 x 10(-6) M. Direct binding studies with purified oxidase, phospholipid-containing as well as(More)
The location and orientation of the heme in yeast cytochrome c peroxidase has been determined from a 2.5 A electron density map phased with two isomorphous mercury derivatives. The noncovalently bound heme is located in a crevice open to the solvent and is oriented so that the two propionate side chains extend toward the surface of the enzyme molecule. The(More)
We have studied the structures of adducts formed between subtilisin BPN' and both benzeneboronic acid and 2-phenylethaneboronic acid by x-ray diffraction techniques. Electron density and difference maps at 2.5 A resolution were computed with phases calculated from a partially refined structure of the native enzyme (R = 0.23 at 2.0 A). Both adducts contain a(More)