Primary structure of major outer-membrane protein I (ompF protein, porin) of Escherichia coli B/r.

In the outer membrane of Gram-negative bacteria hydrophilic pores exist, allowing the diffusion of various low-molecular-weight solutes. These pores are formed by proteins, the porins. In a preliminary communication [Chen, Krämer, Schmidmayr & Henning (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 5014-5017] we presented the primary structure of one of these porins, the 340-amino-acid-residue protein I (ompF protein) from Escherichia coli B/r. In the present paper we give the experimental evidence for this sequence. Two tryptophan positions, one valine position, two aspartic acid positions and nine out of 82 amide determinations have been corrected. To aid further studies on this class of transmembrane proteins, the isolation of most of the constituent peptides is documented.     

The primary nucleotide sequence of nuclear U-2 ribonucleic acid. The 5'-terminal portion of the molecule.

The nuclear U-2 RNA which is highly modified (Reddy, R., Ro Choi, T.S., Henning, D., Shibata, H., Choi, Y.C., and Busch H. (1972) J. Biol. Chem. 247, 7245-7250) contains 13 pseudouridylic acid residues, 10 2'-O-methylated nucleotides and two modified bases including N-2,2, 7-trimethyl guanylic acid in its 5'-terminal portion (69 nucleotides). With the determination of this sequence and its overlap with the 3' portion of the molecule (nucleotides 70 to 196), the over-all nucleotide sequence of this RNA is:(see article). The concentration of modified nucleotides in its 5' portion is greater than for any RNA sequenced thus far.     

Utilization of d-carnitine by Pseudomonas sp. AK 1

Abstract The degradation of chlorophenols by Alcaligenes eutrophus JMP134 (pJP4) was studied. The strain grew on 2,4,6-trichlorophenol or 2,4,6-tribromophenol as the sole carbon and energy source. Complete degradation of 2,4,6-trichlorophenol was confirmed by chloride release and gas chromatography analysis of supernatants from growth cultures. The 2,3,5-, 2,3,4-, 2,3,6-and 2,4,5-isomers of trichlorophenol did not support growth. However, up to 40% of 2,4,5-trichlorophenol was mineralized during growth of A. eutrophus on chemostats fed with either phenol (0.4 mM) or 2,4,6-trichlorophenol (0.4 mM) plus 2,4,5-trichlorophenol (0.1 mM). Growth on 2,4,6-trihalophenols was also observed in A. Eutrophus JMP222, the strain lacking pJP4, suggesting that this new degradative ability reported for A. eutrophus is not related to pJP4 encoded catabolic functions.     

Chirality sensing with pores: reactive signal amplifiers for otherwise undetectable small molecules

Recently, we have introduced a concept to determine enantiomeric excess (ee) with synthetic multifunctional pores (Tanaka and Matile, Chirality 2008;20:307-312). The reported approach is, however, limited to macromolecules and not applicable to small molecules. The problem is that the ability of synthetic pores to respond to chemical stimulation decreases with the size and the charge of the analyte. Here we demonstrate that this problem can be overcome with reactive signal amplifiers that covalently capture elusive analytes for sensitive recognition by the pore. For proof of principle, we use L-lactate and D-lactate as representative pair of enantiomers, L-lactate oxidase as stereospecific signal generator, and cascade blue hydrazide as reactive signal amplifier to capture the produced pyruvate. After stereospecific signal generation and reactive signal amplification, L-lactate was detectable quantitatively and without further optimization in the presence of at least 99% ee of D-lactate. Attempts to sense the traces of impurity in commercial samples of D-lactate gave values in the expected range (99.6% ee expected, 99.3 +/- 0.1% ee found).     

Characterization and functional analysis of the β-1,3-glucanosyltransferase 3 of the human pathogenic fungus Paracoccidioides brasiliensis

The fungus Paracoccidioides brasiliensis causes paracoccidioidomycosis, a systemic granulomatous mycosis prevalent in Latin America. In an effort to elucidate the molecular mechanisms involved in fungus cell wall assembly and morphogenesis, β-1,3-glucanosyltransferase 3 ( Pb Gel3p) is presented here. Pb Gel3p presented functional similarity to the glucan-elongating/glycophospholipid-anchored surface/pH-regulated /essential for pseudohyphal development protein families, which are involved in fungal cell wall biosynthesis and morphogenesis. The full-length cDNA and gene were obtained. Southern blot and in silico analysis suggested that there is one copy of the gene in P. brasiliensis . The recombinant Pb Gel3p was overexpressed in Escherichia coli , and a polyclonal antibody was obtained. The PbGEL3 mRNA, as well as the protein, was detected at the highest level in the mycelium phase. The protein was immunolocalized at the surface in both the mycelium and the yeast phases. We addressed the potential role of Pb Gel3p in cell wall biosynthesis and morphogenesis by assessing its ability to rescue the phenotype of the Saccharomyces cerevisiae gas1 Δ mutant. The results indicated that Pb Gel3p is a cell wall-associated protein that probably works as a β-1,3-glucan elongase capable of mediating fungal cell wall integrity.