Specific water-soluble substrates for chymotrypsin: Attempts for compensating diminished P1-S1 interactions

1988 ◽  
Vol 53 (11) ◽  
pp. 2884-2889 ◽  
Author(s):  
Volker Schellenberger ◽  
Ute Schellenberger ◽  
Hans-Dieter Jakubke
Keyword(s):  
Amino Acid ◽  
Methyl Esters ◽  
Water Soluble ◽  
Amino Acid Residues ◽  
Substrate Properties ◽  
Ester Moiety ◽  
Benzyl Esters ◽  
Peptide Esters ◽  
Acyl Donors ◽  
Positively Charged

N-Maleyl-L-amino acid and peptide esters were synthesized and employed as substrates for α-chymotrypsin. From the kcat/KM values can be suggested that benzyl esters are significantly better substrates than the appropriate methyl esters. Further improvement in the substrate properties results from the introduction of the p-nitrobenzyl ester moiety. The choline ester of benzyloxycarbonyl-L-phenylalanine with the highest kcat/KM value confirmed the P1' leaving group specificity for positively charged residues. From the kinetic data can be concluded that acyl donors with high kcat/KM values, which are useful in kinetically controlled enzymatic peptide synthesis, need not contain aromatic amino acid residues in the P1 position.

scholarly journals Positively charged amino acid residues located similarly in sea anemone and scorpion toxins

1994 ◽  
Vol 269 (24) ◽  
pp. 16785-16788
Author(s):  
E.P. Loret ◽  
R.M. del Valle ◽  
P. Mansuelle ◽  
F. Sampieri ◽  
H. Rochat
Keyword(s):  
Amino Acid ◽  
Sea Anemone ◽  
Amino Acid Residues ◽  
Scorpion Toxins ◽  
Positively Charged

Mutational analysis of positively charged amino acid residues of Uukuniemi phlebovirus nucleocapsid protein

2012 ◽  
Vol 167 (1) ◽  
pp. 118-123 ◽  
Author(s):  
Anna Katz ◽  
Alexander N. Freiberg ◽  
Vera Backström ◽  
Liisa Holm ◽  
Antti Vaheri ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nucleocapsid Protein ◽  
Mutational Analysis ◽  
Amino Acid Residues ◽  
Positively Charged

scholarly journals AplA, a Member of a New Class of Phycobiliproteins Lacking a Traditional Role in Photosynthetic Light Harvesting

2004 ◽  
Vol 186 (21) ◽  
pp. 7420-7428 ◽  
Author(s):  
Beronda L. Montgomery ◽  
Elena Silva Casey ◽  
Arthur R. Grossman ◽  
David M. Kehoe
Keyword(s):  
Amino Acid ◽  
Tertiary Structure ◽  
Light Harvesting ◽  
Water Soluble ◽  
Amino Acid Residues ◽  
Subunit Interactions ◽  
Traditional Role ◽  
Light Harvesting Complexes ◽  
Fremyella Diplosiphon ◽  
New Class

ABSTRACT All known phycobiliproteins have light-harvesting roles during photosynthesis and are found in water-soluble phycobilisomes, the light-harvesting complexes of cyanobacteria, cyanelles, and red algae. Phycobiliproteins are chromophore-bearing proteins that exist as heterodimers of α and β subunits, possess a number of highly conserved amino acid residues important for dimerization and chromophore binding, and are invariably 160 to 180 amino acids long. A new and unusual group of proteins that is most closely related to the allophycocyanin members of the phycobiliprotein superfamily has been identified. Each of these proteins, which have been named allophycocyanin-like (Apl) proteins, apparently contains a 28-amino-acid extension at its amino terminus relative to allophycocyanins. Apl family members possess the residues critical for chromophore interactions, but substitutions are present at positions implicated in maintaining the proper α-β subunit interactions and tertiary structure of phycobiliproteins, suggesting that Apl proteins are able to bind chromophores but fail to adopt typical allophycocyanin conformations. AplA isolated from the cyanobacterium Fremyella diplosiphon contained a covalently attached chromophore and, although present in the cell under a number of conditions, was not detected in phycobilisomes. Thus, Apl proteins are a new class of photoreceptors with a different cellular location and structure than any previously described members of the phycobiliprotein superfamily.

scholarly journals Positive Charges on Lysine Residues of the Extrinsic 18 kDa Protein Are Important to Its Electrostatic Interaction with Spinach Photosystem II Membranes

2005 ◽  
Vol 37 (11) ◽  
pp. 737-742 ◽  
Author(s):  
Jin-Peng Gao ◽  
Zhen-Hua Yong ◽  
Feng Zhang ◽  
Kang-Cheng Ruan ◽  
Chun-He Xu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Methyl Esters ◽  
Binding Activity ◽  
Water Soluble ◽  
Carboxyl Groups ◽  
Amino Groups ◽  
Charged Amino Acids ◽  
Lysine Residues ◽  
Glycine Methyl Ester ◽  
Positively Charged

Abstract To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with Nsuccinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4–10 and 10–14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3–4 carboxyl groups were modified by reaction with 100 mM GME. Neutralization of negatively charged carboxyl groups with GME did not alter the binding activity of the extrinsic 18 kDa protein. However, the NSP-modified 18 kDa protein, in which the positively charged amino groups had been modified to uncharged methyl esters, failed to bind with the PSII membrane in the presence of the extrinsic 23 kDa protein. This defect can not be attributed to structural or conformational alterations imposed by chemical modification, as the fluorescence and circular dichroism spectra among native, GME and NSP-modified extrinsic 18 kDa proteins were similar. Thus, we have concluded that the positive charges of lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSII membranes in the presence of the extrinsic 23 kDa protein. Furthermore, it was found that the negative charges of carboxyl groups of this protein did not participate in binding with the extrinsic 23 kDa protein associated with PSII membranes.

Detection and Location of N-Methyl-amino-acid Residues in N-Acyloligopeptide Methyl Esters by Mass Spectrometry

Nature ◽  
1968 ◽  
Vol 217 (5128) ◽  
pp. 547-548 ◽  
Author(s):  
B. C. DAS ◽  
S. D. GÉRO ◽  
E. LEDERER
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Methyl Esters ◽  
Amino Acid Residues
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