Partial amino acid sequences of botulinum neurotoxins types B and E.

Clostridium botulinum type E neurotoxin, a single-chain protein of Mr 147,000, was purified and subjected to amino acid sequencing. The same was done for single-chain botulinum type B neurotoxin (Mr 152,000), and for the heavy and light chains (Mr 104,000 and 51,000 respectively) derived from type B by limited trypsin digestion. Twelve to eighteen residues were identified and the following conclusions were drawn: The light chain of the nicked (dichain) type B is derived from the N-terminal one-third of the single-chain (unnicked) parent neurotoxin; sequence homologies are present between single-chain types B and E and the light chain of the nicked type A [J.

Unwinding associated with synapsis of DNA molecules by recA protein.

In the presence of adenosine 5'-[gamma-thio]triphosphate, a nonhydrolyzable analog of ATP, Escherichia coli recA protein extensively unwinds duplex DNA in a reaction that is strongly stimulated by either homologous or heterologous single-stranded DNA [Cunningham, R.P., Shibata, T.

Serine transhydroxymethylase activity in vertebrate retina.

The presence of serine transhydroxymethylase (STHM; EC 2.1.2.

Physiological and psychological aspects of anxiety in psychiatric patients and normal subjects.

Physiological (Skin conductance) and Psychological (State-trait anxiety) measures of anxiety were employed to assess the level of anxiety in 10 anxious neurotics, 10 schizophrenics and 10 normal subjects. Both the Physiological and Psychological measures were sensitive in detecting the level of anxiety in normals and patients. But interrelationships between these two measures were very poor.

Polar branch migration promoted by recA protein: effect of mismatched base pairs.

Escherichia coli recA protein makes joint molecules from single-stranded circular phage DNA (viral or plus strand) and homologous linear duplex DNA by a polar reaction that displaces the 5' end of the plus strand from the duplex molecule [Kahn, R., Cunningham, R. P.

Synthesis of isotopically labeled saturated fatty acids.

An approach to the synthesis of isotopically labeled saturated fatty acids is outlined which is based on the copper-catalyzed coupling of an omega-bromo acid with an isotopically labeled Grignard reagent. The method provides high yields of pure products and offers considerable flexibility in the type of isotopically enriched compound that can be prepared.-DasGupta, S.

Polarity of heteroduplex formation promoted by Escherichia coli recA protein.

When recA protein pairs circular single strands with linear duplex DNA, the circular strand displaces its homolog from only one end of the duplex molecule and rapidly creates heteroduplex joints that are thousands of base pairs long [DasGupta, C., Shibata, T., Cunningham, R.

Homologous pairing in genetic recombination. The pairing reaction catalyzed by Escherichia coli recA protein.

Purified recA protein, which is essential for genetic recombination of Escherichia coli, catalyzed ATP-dependent homologous pairing of double-stranded DNA and single-stranded fragments to form D-loops. When the double-stranded DNA was nicked circular DNA (form II) or linear DNA (form III), the reaction proceeded nearly linearly during 30 min of incubation at 37 degrees C. When the double-stranded DNA was superhelical (form I), anomalous kinetics was observed.

The behavior of carbenicillin as a nonreabsorbable anion.

In order to study the mechanism of hypokalemic alkalosis which occurs in some patients being treated with disodium carbenicillin, renal clearance experiments were carried out in rats and observations were made on electrical changes in isolated toad bladders. In rats maintained on a sodium-free diet, intravenous infusion of carbenicillin at 40 mg. per hour resuited in an immediate diuresis characterized by a striking increase in K and NH4 excretion, and progressive acidification of the urine.