scholarly journals A complete separation of dimethylaminoazobenzenesulphonyl-amino acids. Amino acid analysis with low nanogram amounts of polypeptide with dimethylaminoazobenzenesulphonyl chloride

1982 ◽  
Vol 203 (3) ◽  
pp. 803-806 ◽  
Author(s):  
J Y Chang ◽  
R Knecht ◽  
D G Braun
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
High Sensitivity ◽  
Complete Separation ◽  
Light Chains ◽  
Composition Analysis ◽  
Amino Acid Residues ◽  
Immunoglobulin Light Chains ◽  
New System

A chromatographical system has been developed to give a complete baseline separation of all dimethylaminoazobenzenesulphonyl (DABS)-amino acids for high-sensitivity amino acid analysis [Chang, Knecht & Braun (1981) Biochem. J. 199, 547-556]. The system, which uses a Merck RP-18 column with phosphate buffer (12 mM, pH 6.5)/acetonitrile mixture, allows reliable analysis of DABS-amino acids at the 1-2 pmol level. The accuracy of this new system is demonstrated by the composition analysis of two immunoglobulin light chains (214 amino acid residues) with differences at only three amino acid residue positions.

Comparative study of rye and thymus histones: amino acid analysis and tryptic fingerprinting

1977 ◽  
Vol 55 (7) ◽  
pp. 721-727 ◽  
Author(s):  
Paul Nadeau ◽  
Dominick Pallotta ◽  
Jean-G. Lafontaine
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Secale Cereale ◽  
Primary Structure ◽  
Amino Acid Analysis ◽  
General Pattern ◽  
The Other ◽  
Amino Acid Residues ◽  
Additional Segment ◽  
Similar Amino Acid

Amino acid composition and tryptic fingerprints of rye (Secale cereale) H1, H2B (PHI), and H2A (PHII) histones indicate the presence of major differences between these and the corresponding calf or rabbit fractions. In addition to variations for other amino acids, fraction H1 from rye contains twice as much arginine as the corresponding animal fraction; the plant H2B (PHI) and H2A (PHII) histones show lysine to arginine ratios greater than those of their animal counterparts. The tryptic maps of the same proteins appear to differ between plants and animals by the number and the general pattern of the peptides, as well as by the quantity and distribution of the arginine-containing peptides. Such results suggest the presence of differences in the primary structure of the calf and rye lysine-rich and moderately lysine-rich histones. Furthermore, the possibility is ruled out that each of these plant histones consists of an animal-like protein with an additional segment of 20–30 amino acid residues. On the other hand, the rye and calf arginine-rich fractions H3 and H4 show similar amino acid compositions and tryptic peptides maps.

High-sensitivity amino acid analysis of stained peptides and proteins from a sodium dedecyl sulphate-polyacrylamide slab gel

1986 ◽  
Vol 354 ◽  
pp. 463-470 ◽  
Author(s):  
S. Shoji ◽  
M. Ichikawa ◽  
T. Yamaoka ◽  
T. Funakoshi ◽  
Y. Kubota
Keyword(s):  
Amino Acid ◽  
Amino Acid Analysis ◽  
High Sensitivity

The C-terminal sequence of amino acid residues of κ-casein isolated from buffalo's milk

1967 ◽  
Vol 34 (1) ◽  
pp. 85-88 ◽  
Author(s):  
M. H. Abd El-Salam ◽  
W. Manson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Peptide Chain ◽  
Amino Acid Residues ◽  
Terminal Sequence ◽  
Carboxypeptidase A ◽  
Phosphorous Content ◽  
Single Peptide

SummaryWhen κ-casein from buffalo's milk was treated with carboxypeptidase A (EC 3. 4. 2. 1),4 amino acids, valine, threonine, serine and alanine were released from the protein in a manner consistent with the view that they originate in the C-terminal sequence of a single peptide chain. The amounts produced suggest a minimum molecular weight for buffalo κ-casein of approximately 17000, in agreement with the value calculated from the phosphorous content on the basis of the presence of 2 phosphorus atoms/molecule. A comparison is made with the C-terminal sequence reported for bovine κ-casein.

scholarly journals SPECIFICITY IN THE COMBINATION OF FD FRAGMENTS WITH L CHAINS TO FORM HAPTEN-BINDING SITES

1966 ◽  
Vol 123 (5) ◽  
pp. 921-934 ◽  
Author(s):  
O. A. Roholt ◽  
G. Radzimski ◽  
D. Pressman
Keyword(s):  
Amino Acid ◽  
Propionic Acid ◽  
Binding Sites ◽  
Amino Acid Analysis ◽  
Binding Activity ◽  
Light Chains ◽  
Antibody Activity ◽  
Fc Fragment ◽  
Fab Fragments ◽  
Correct Alignment

In the work reported here we have shown that light chains and Fd fragments can be separated completely in propionic acid and then recombined to form Fab fragments with antibody activity. This experiment indicates that in the recombination a correct alignment of the Fd fragments and the L chains occurs to give a competent antibody site, just as occurs with the recombination of separated heavy and light chains of the antibody; thus the Fc fragment is not required for correct alignment. Fd fragments of antibody alone show very low binding activity toward the specific hapten. As is the case for the combination of heavy and light chains, the combination of Fd fragments and light chains also requires that both components come from antibody from the same rabbit in order to give binding sites. When they are derived from different rabbits producing antibody against the same antigen, they still give Fab fragments as shown by immunoelectrophoresis but do not have competent binding sites. An important observation is that the subunits of the papain digest fractions, FabI and FabII, have the capacity to cross-combine to form active Fab fragments with competent binding sites. FdI from FabI combines with LII chains from FabII to give the composite (FdI-LII) with good binding activity. Likewise, the composite (FdII-LI) has good binding activity. The composites from the two types of antibody molecules yielding different Fab fragments have antibody activity although heretofore these molecules have appeared to be different on the bases of chromatography and amino acid analysis. There is also a preferential combination of the Fd fragments to combine with the correct L fragments to give binding sites since this combination takes preference over the combination of Fd fragments of antibody with light chains of normal globulin (or of light chains of antibody with Fd fragments of normal globulin).

Structural characterization of folded and extended conformations in peptides containing γ amino acids with proteinogenic side chains: crystal structures of γn, (αγ)n and γγδγ sequences

2015 ◽  
Vol 39 (5) ◽  
pp. 3319-3326 ◽  
Author(s):  
Madhusudana M. B. Reddy ◽  
K. Basuroy ◽  
S. Chandrappa ◽  
B. Dinesh ◽  
B. Vasantha ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crystal Structures ◽  
Structural Characterization ◽  
Side Chains ◽  
Amino Acid Residues

γn amino acid residues can be incorporated into structures in γn and hybrid sequences containing folded and extended α and δ residues.

scholarly journals SLC6A14, a Pivotal Actor on Cancer Stage: When Function Meets Structure

2019 ◽  
Vol 24 (9) ◽  
pp. 928-938 ◽  
Author(s):  
Luca Palazzolo ◽  
Chiara Paravicini ◽  
Tommaso Laurenzi ◽  
Sara Adobati ◽  
Simona Saporiti ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Amino Acids ◽  
Amino Acid ◽  
Molecular Dynamics Simulations ◽  
Electrostatic Interactions ◽  
Amino Acid Residues ◽  
Dibasic Amino Acid ◽  
Novel Target ◽  
Function Relationship ◽  
Dynamics Simulations

SLC6A14 (ATB0,+) is a sodium- and chloride-dependent neutral and dibasic amino acid transporter that regulates the distribution of amino acids across cell membranes. The transporter is overexpressed in many human cancers characterized by an increased demand for amino acids; as such, it was recently acknowledged as a novel target for cancer therapy. The knowledge on the molecular mechanism of SLC6A14 transport is still limited, but some elegant studies on related transporters report the involvement of the 12 transmembrane α-helices in the transport mechanism, and describe structural rearrangements mediated by electrostatic interactions with some pivotal gating residues. In the present work, we constructed a SLC6A14 model in outward-facing conformation via homology modeling and used molecular dynamics simulations to predict amino acid residues critical for substrate recognition and translocation. We docked the proteinogenic amino acids and other known substrates in the SLC6A14 binding site to study both gating regions and the exposed residues involved in transport. Interestingly, some of these residues correspond to those previously identified in other LeuT-fold transporters; however, we could also identify a novel relevant residue with such function. For the first time, by combined approaches of molecular docking and molecular dynamics simulations, we highlight the potential role of these residues in neutral amino acid transport. This novel information unravels new aspects of the human SLC6A14 structure–function relationship and may have important outcomes for cancer treatment through the design of novel inhibitors of SLC6A14-mediated transport.

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