ABSTRACT
The 3psigma(u)D (3)Sigma(u) (+) Rydberg state of N(2) is studied experimentally using two high-resolution spectroscopic techniques. First, the forbidden D (3)Sigma(u) (+)-X (1)Sigma(g) (+) transition is observed for the first time via the (0,0) band of (14)N(2) and the (1,0) band of (15)N(2), using 1 extreme-ultraviolet +1 ultraviolet two-photon-ionization laser spectroscopy. Second, the Rydberg-Rydberg transition D (3)Sigma(u) (+)-E (3)Sigma(g) (+) is studied using near-infrared diode-laser photoabsorption spectroscopy, thus extending the previous measurements of Kanamori et al. [J. Chem. Phys. 95, 80 (1991)], to higher transition energies, and thereby revealing the (2,2) and (3,3) bands. The combined results show that the D(v=0-3) levels exhibit rapidly increasing rotational predissociation as v increases, spanning nearly four orders of magnitude. The D-state level structure and rotational predissociation signature are explained by means of a coupled-channels model which considers the electrostatically coupled (3)Pi(u) Rydberg-valence manifold, together with a pure-precession L-uncoupling rotational interaction between the 3psigma(u)D (3)Sigma(u) (+) and 3ppi(u)G (3)Pi(u) Rydberg p-complex components.
ABSTRACT
The complete amino acid sequence of Japanese chestnut (Castanea crenata Sieb. et Zucc.) agglutinin (CCA) was determined. Analysis by SIMS of the acidic peptide obtained by pepsin digestion revealed that the N-terminal amino acid sequence should be Acetyl-Met-Glu-Glu. Prior to sequence analysis, redetermination of cysteine residues indicated the presence of one cysteine residue per subunit. The complete sequence was determined by endoproteinase Arg-C and Achromobacter protease I digestion, and CNBr cleavage. CCA consists of 309 amino acid residues with a high content of glycine (16.5 mol%) and one cysteine residue. The calculated molecular mass was 33, 387 Da including the N-terminal acetyl group. C-terminal sequence analysis of intact CCA gave only one sequence, HMEYF, indicating that no heterogeneous CCA formed by posttranslational cleavage at the C-terminal region, as occurs in some legume lectins. Analysis of the sequence of CCA itself revealed that CCA could be divided into two structural domains, the N-domain and the C-domain, almost at the center. These domains share about 35% identical residues, so CCA has a repeat sequence. Also, both domains show a homology to jacalin-related lectins with 27-38% identity. These results suggest that the structure of CCA resembles two molecules of jacalin-related lectin.
Subject(s)
Agglutinins/genetics , Plant Proteins/genetics , Amino Acid Sequence , Molecular Sequence Data , Plants , Sequence Alignment , Sequence Analysis, ProteinABSTRACT
The Ã(010)3Delta-;X(010)3Pi(b) band spectrum of the CCO radical has been studied in the region from 11,808 to 11,919 cm-1 by near-infrared diode-laser spectroscopy. A least-squares fit has been made using only part of the observed Ã(010)3Delta-;X(010)3Pi(b) band transitions to obtain molecular constants for the Ã(010)3Delta state, removing transitions with upper levels of irregular behavior. The spin-orbit parameter and the subband origin determined in the present analysis have been discussed in relation to higher order contributions to the Renner-Teller effect. Copyright 1999 Academic Press.
ABSTRACT
A new singlet-singlet absorption band between Rydberg states of the nitrogen molecule was studied by near-infrared diode laser spectroscopy in the 1.3 &mgr;m region. An analysis was made for the band to establish line assignments and determine molecular parameters for both the lower and the upper vibronic states. As a result of the analysis, this band was assigned to the c1Piu-a"1Sigmag+, v = 1-0 band. The anomaly of the Lambda-type doubling structure in the c1Piu (v = 1) state was discussed in connection with the interaction with the b'1Sigmau+ (v = 4) state. The predissociation in the c1Piu (v = 1) state was also discussed relating with the line broadening observed. Copyright 1997 Academic Press. Copyright 1997Academic Press
ABSTRACT
This report describes the anti-platelet aggregation activity of 48 pyrazines. Among alkyl- and arylpyrazines tested, 2,3-diphenylpyrazines showed the strongest anti-platelet aggregation activity. Then, various substituents were introduced into the phenyl groups, and the 2,3-bis(p-methoxyphenyl)pyrazine derivatives were consequently found to possess considerably strong inhibitory activity.
Subject(s)
Platelet Aggregation Inhibitors/pharmacology , Platelet Aggregation/drug effects , Pyrazines/pharmacology , Animals , Arachidonic Acid/toxicity , Collagen/toxicity , Drug Evaluation, Preclinical , Platelet Aggregation Inhibitors/chemistry , Pyrazines/chemistry , Rabbits , Structure-Activity RelationshipABSTRACT
The A(020)kappa3Pi-X3Sigma-(000) and A3Pii(001)-X3Sigma-(000) bands of the CCO radical have been investigated by laser spectroscopy with two types of tunable laser system. An analysis was made simultaneously for both the bands to establish line assignments and determine molecular constants for both the A(020) and A(001) states. A coupling constant between these two states was also determined by assuming the interaction to be of Fermi type.
