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Biomedical subjects

R M Sweet

Publications and source records attributed to R M Sweet.

68 records · Page 4Linked to original sources
PubMed1980

Three-dimensional structures of C-phycocyanin and B-phycoerythrin at 5-A resolution.

Single crystal x-ray diffraction studies are proceeding on two phycobiliproteins: C-Phycocyanin from Anabaena variabilis and B-Phycoerythrin from Porphyridium cruentum. C-Phycocyanin consists of six alpha and six beta subunits. A three-dimensional x-ray diffraction study of this light-harvesting protein (P6(3); a = b = 154.1 A, c = 40.1 A) at 5-A resolution shows that the molecule is 110 A in diameter, 40 A thick, with a 20-A diameter central channel. It can be divided into three separate domains related by the crystallographic 3 and contains long, columnar regions of density, presumed to represent alpha helix. B-Phycoerythrin is composed of 6 alpha, 6 beta, and a gamma subunit. A 5.25-A resolution study of this protein (R3, a = b = 189 A, c = 60 A) indicates that the molecule is 107 A in diameter and 55 A thick, has 32-D3 symmetry, and can be divided into six regions. The gamma chain lies on a crystallographic 3 and undergoes symmetric disordering. A region of low and unstructured density in the center of the molecule is presumably occupied by this gamma chains. These two low resolution structures are compared with regard to differences in quaternary structure.

Cyanobacteria↗
PubMed1979

Eosinophilic granuloma in the temporal bone.

Eosinophilic granuloma is an uncommon granulomatous disease which can affect the temporal bone. Although initially silent, the disease may erode the mastoid cortex, destroy the tegmen and extend into the cranial vault, as well as erode the semicircular canals or cochlea. These lesions almost always become infected and can be confused with chronic otomastoiditis. Equally important, temporal bone involvement may represent only one manifestation of a multifocal disease. Between 1940 and 1978, 19 cases of eosinophilic granuloma involving the temporal bone have been recorded in the Armed Forces Institute of Pathology Registry. Most recently, a 24-year-old white boatswain's mate was sent to the National Naval Medical Center for treatment of unifocal disease which originated in his right mastoid bone. He subsequently underwent modified radical mastoidectomy and received 2500 R cobalt therapy to the temporal bone following surgery. His case history is detailed and the problem of eosinophilic granuloma in the temporal bone is reviewed in depth.

Adult↗
PubMed1979

Lingual thyroid.

Explore the source record for details and available documents.

Choristoma↗
PubMed1978

Jejunoileal bypass surgery and granulomatous disease of the kidney and liver.

A 26-year-old woman, who had undergone jejunoileal bypass surgery six years previously for obesity, had symptoms of intermittent fever, myalgia, polyarthralgia, and aseptic joint swelling. These symptoms commenced one year after her surgery and gradually grew in intensity and frequency of occurrence. The patient, observed to have moderately decreased renal function, hyperoxaluria, and circulating cryoglobulins, underwent liver and renal biopsies. Both organ specimens demonstrated granulomatous involvement, but the kidneys exhibited no evidence of oxalate deposition. The findings of circulating cryoglobulins and suppression of symptoms with doxycycline, taken collectively with the circumstances surrounding this case, suggest that the observed granulomatous disease may be due to systematically adsorbed bacterial antigen(s).

Adult↗
PubMed1977

Preliminary crystallographic investigations of two phycobiliproteins.

Single crystal x-ray diffraction investigations are in progress on two phycobiliproteins. C-phycocyanin from Anabaena variabilis crystallizes in space group P63 with a = b = 154 A and c = 40 A. The crystallographic asymmetric unit is (alphabeta)2 with a total molecular mass of 7.0-10(4) daltons. B-phycoerythrin from Porphyridium cruentum crystallizes in space group R3 with a = b = 189 A and c = 60 A. This molecule has the unusual molecular stoichiometry (alphabeta)6gamma and the crystallographic asymmetric unit is (alphabeta)2gamma1/3. This requires that the gamma chain undergo a perfect 3-fold disordering about the crystallographic 3 axis, i.e. the gamma chain must occupy three symmetry-equivalent positions, each with an occupancy of one-third.

Cyanobacteria↗
PubMedDate not supplied

Preparation and crystallization of a complex between human adenovirus serotype 2 proteinase and its 11-amino-acid cofactor pVIc.

Crystals have been obtained of the recombinant human adenovirus serotype 2 proteinase (AVP) in a complex with its 11-amino-acid cofactor pVIc. AVP-pVIc complexes were formed by the incubation of AVP with a 1.2-fold molar excess of pVIc prior to the crystallization trials. Diffraction-quality crystals were obtained at 18 degrees C by the vapor-diffusion method with 5.6 mg/ml AVP-pVIc in 1.4 M sodium acetate and 0.1 M Hepes, pH 7.5. Diffraction data (99% complete to 2.6 A resolution with Rmerge of 0.077) were collected from native crystals at room temperature at beamline X12-C at the National Synchrotron Light Source. The crystals belong to space group P6(1) with unit cell dimensions a = b = 114.2 A, c = 50.1 A; alpha = beta = 90 degrees, gamma = 120 degrees. The unit cell dimensions and likely mass of the molecular species in the crystals were consistent with there being one 25,000-Da complex (1:1) per asymmetric unit. Additionally, one heavy-atom derivative, obtained by the soaking of preformed crystals, was isomorphous to the native crystal. Diffraction data obtained on these crystals were 95% complete to 3.0 A resolution with an Rmerge of 0.076. Difference-Patterson analysis indicates three heavy atom sites in the derivative asymmetric unit.

Crystallization↗