Conversion of the L-Serine Residue to an L-Cysteine Residue in Peptides<sup>*</sup>

Zioudrou, Christine; Wilchek, Meir; Patchornik, A.

doi:10.1021/bi00885a018

Cited by 36 publications

(19 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The following reaction conditions gave good yields. Eleven MAmoles of subtilisin in 20 ml, pH 7, 0.1 M phosphate buffer, and 10-4 M CaCl2 were reacted for 2 hr with 15 ,smoles of phenylmethanesulfonyl fluoride. The esterolytic activity against either acetyl tyrosine ethyl ester or p-nitrophenyl acetate dropped to less than 1 per cent of the original activity.…”

mentioning

confidence: 99%

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

Neet¹,

Koshland²

1966

Proc. Natl. Acad. Sci. U.S.A.

191

View full text Add to dashboard Cite

Since the disruption of the three-dimensional structure of a protein can cause loss of enzyme activity, the interpretation of modification studies at the active sites of enzymes becomes particularly difficult. It is necessary to modify catalytic residues to establish their essentiality to the catalytic process, but any modification leading to loss in activity might also be explained as an effect on three-dimensional structure. Moreover, it is not clear how much change in the spatial position of functional groups can be tolerated by the enzyme. Although some change is apparently allowed in residues involved in binding or tertiary structure,'-3 it would be expected that enzyme activity should be even more sensitive to changes in amino acids directly involved in catalysis. Therefore, it would be desirable to modify the catalytic residues in as minor a way as possible ill order to understand the function of these residues.It has been possible to transform the serine residue at the active site of chymotrypsin to a dehydroalanine residue, a change which converted the serine to a smaller residue and thus removed any steric access ambiguities in the interpretation of the role of the serine.4 Such a modification, however, involved a considerable change in the chemical properties of the affected moiety, and it was desirable to attempt a conversion to a residue more nearly similar to that of the original serine. Such a residue is cysteine since the SH group of cysteine possesses steric and chemical properties similar to those of the OH group of serine. The van der Waals radii of oxygen and sulfur are 1.40 and 1.85 A, respectively, and the covalent radii are 0.66 and 1.04 A, respectively.6 Since the two groups react similarly in hydrolyses, such a chemical transformation would be minimal, both chemically and sterically. The SH group is, in general, somewhat more reactive than the OH group either as an attacking nucleophile or as a leaving group.7-10To effect such a change in chymotrypsin is difficult because the chemical manipulations require the presence of active sulfide compounds which tend to break the disulfide bridges in the molecule. Therefore, subtilisin, a proteolytic enzyme with properties like those of chymotrypsin but containing no disulfide bridges, was chosen for the desired conversion. The serine at the active site of subtilisin undergoes inactivation with diisopropylfluorophosphate,'1 and the specificity of the enzyme is similar in many ways to that of chymotrypsin and other serine proteases.12 Chymotrypsin shows unusual reactivity with sulfonyl fluorides11 and this reactivity was also found to extend to subtilisin. With the use of C14-labeled phenylmethanesulfonyl fluoride, a rapid and stoichiometric inhibition of the enzyme was obtained yielding 0.95 4 0.05 mole of phenylmethanesulfonyl group per mole of subtilisin. Apparently the phenylmethanesulfonyl group reacted by a prior binding to the active site, just as in the case of chymotrypsin, since the reactivity of the similar reagent, toluene sulfonyl fluor...

show abstract

mentioning

confidence: 99%

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

Neet¹,

Koshland²

1966

Proc. Natl. Acad. Sci. U.S.A.

191

View full text Add to dashboard Cite

show abstract

“…Transformative manipulations in nucleic acids [15] lead directly from a connection between structure and 'gene', yet the more complex question of information closer to functional output (e. g. in proteins) has barely been touched on, despite profound insights set down over 50 years ago. [17,21] This brief essay will explore a few illustrative areas with the goal of capturing the distinctive nature of chemical analysis of biology, which to me lies in great part in the precision that it might bring to bear.…”

Section: What Has Chemical Biology Done and What Is It Doing?mentioning

confidence: 99%

“…An example that I often return to, is that of what is loosely described as mutagenesis. Transformative manipulations in nucleic acids lead directly from a connection between structure and ‘gene’, yet the more complex question of information closer to functional output (e. g. in proteins) has barely been touched on, despite profound insights set down over 50 years ago ,…”

Section: Introductionmentioning

confidence: 99%

A Brief Manifesto for Chemical Ingenuity and Insight in the Heart of Biology: A Time is Right for Sophistication not Simplification?

Davis

2018

Israel Journal of Chemistry

View full text Add to dashboard Cite

“…A point of interest in the characterization of I1 was the absence of a nitrile absorption band at 4.4-4.5 p. The occasional marked diminution or absence of this band in certain oxygen-rich compounds has been noted previously (47). Subsequent attempts were unsuccessful in displacing the tosyl group of 111 by treatment with thioacetate (as with serine conversion to cysteine (48,49)), or with thiobenzoate (as reported for the thiobenzoylation of N-O-ditosyl-4-HypOCH3 (50)).…”

Section: N-acetyl-o-tosyl-4-hydroxy-~-proline Amide N-mentioning

confidence: 99%

Synthesis of Peptides and Derivatives of 3‐ and 4‐ Hydroxyproline

Adams

1976

International Journal of Peptide and Protein Research

View full text Add to dashboard Cite

Synthesis and properties are reported for a number of peptides and related derivatives of 3‐hydroxy‐L‐proline and 4‐hydroxy‐L‐proline. These were made for several different purposes, namely, synthesis of N‐acetyl‐O‐tosyl‐4‐hydroxy‐L‐proline amide as a model for chemical reduction of peptide‐bound hydroxyproline, synthesis of tripeptides with the sequence glycyl‐4‐hydroxy‐L‐prolyl‐X, synthesis of the naturally occurring sequence, glycyl‐3‐hydroxy‐L‐prolyl‐4‐hydroxy‐L‐proline, and monomers for polymerization to yield the sequence ‐glycyl‐prolyl‐4‐hydroxy‐L‐prolyl‐.

show abstract

Conversion of the L-Serine Residue to an L-Cysteine Residue in Peptides^*

Abstract: The reaction of thioacetate ion with O-ptoluenesulfonyl-L-serine peptides in V,/V-dimethylformamide or aqueous media (pH 7) results in the quantitative formation of optically active 5-acetyl-Lcysteine peptides via an Sn2 displacement mechanism.

Cited by 36 publications

References 40 publications

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

A Brief Manifesto for Chemical Ingenuity and Insight in the Heart of Biology: A Time is Right for Sophistication not Simplification?

Synthesis of Peptides and Derivatives of 3‐ and 4‐ Hydroxyproline

Contact Info

Product

Resources

About

Conversion of the L-Serine Residue to an L-Cysteine Residue in Peptides*

Abstract: The reaction of thioacetate ion with O-ptoluenesulfonyl-L-serine peptides in V,/V-dimethylformamide or aqueous media (pH 7) results in the quantitative formation of optically active 5-acetyl-Lcysteine peptides via an Sn2 displacement mechanism.

Cited by 36 publications

References 40 publications

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

The conversion of serine at the active site of subtilisin to cysteine: a "chemical mutation".

A Brief Manifesto for Chemical Ingenuity and Insight in the Heart of Biology: A Time is Right for Sophistication not Simplification?

Synthesis of Peptides and Derivatives of 3‐ and 4‐ Hydroxyproline

Contact Info

Product

Resources

About

Conversion of the L-Serine Residue to an L-Cysteine Residue in Peptides^*