Mechanism of the serine protease reaction. Stereoelectronic, structural, and kinetic considerations as guidelines to deduce reaction paths

Dutler, Hans; Bizzozero, Spartaco A.

doi:10.1021/ar00165a005

Cited by 31 publications

(19 citation statements)

References 28 publications

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“…A tetrahedral transition state stabilized by two additional hydrogen bonds between substrate and enzyme is formed. The reaction is accompanied by a proton transfer from the Ser 195 oxygen to the nitrogen of His 57 [25].…”

Section: Resultsmentioning

confidence: 99%

Proteolytically stable peptides by incorporation of α-Tfm amino acids

et al. 1997

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A series of model peptides containing alpha-trifluoromethyl-substituted amino acids in five different positions relative to the predominant cleavage site of the serine protease alpha-chymotrypsin was synthesized by solution methods to investigate the influence of alpha-Tfm substitution on the proteolytic stability of peptides. Proteolysis studies demonstrated absolute stability of peptides substituted to the P1 position and still considerable proteolytic stability for peptides substituted at the P2 and P'2 positions compared with the corresponding unsubstituted model peptide. Comparison with peptides containing the fluorine-free disubstituted amino acid alpha-aminoisobutyric acid allowed to separate electronic from steric effects. Furthermore, the absolute configuration of the alpha-Tfm-substituted amino acid was found to exert considerable effects on the proteolytic stability, especially in P'1 substituted peptides. Investigations of this phenomenon using empirical force field calculations revealed that in the (S,R,S)-diasteromer the steric constraints exhibited by the alpha-Tfm group can be outweighed by an advantageous interaction of the flourine atoms with the serine side chain of the enzyme. In contrast, a favourable interaction between substrate and enzyme is impossible for the (S,S,S)-diastereomer.

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Section: Resultsmentioning

confidence: 99%

Proteolytically stable peptides by incorporation of α-Tfm amino acids

et al. 1997

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“…Meanwhile, based on the stereo-electronic consideration, it has been suggested that inversion of leaving nitrogen of the amine group takes place at the TI to favor the proton transfer to the leaving group and the cleavage of the C-N bond. 11, 26, 27 To unambiguously elucidate this interesting mechanistic puzzle regarding the acylation tetrahedral intermediate has important implications in understanding serine protease substrate specificity as well as inhibition mechanisms, but is very difficult to be achieved by experimental means alone.…”

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confidence: 99%

“…Instead, the change between two distinct TI configurations only involves a subtle reorientation of the histidine ring. In order to examine other hypotheses that the nitrogen-inversion 11, 26, 27 or rotation of the leaving group around C-N bond 11, 19 takes place at the tetrahedral intermediate (TI) to favor the forward reaction, we have also calculated the improper angle τ and torsion angle ω (see Fig. 3a).…”

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confidence: 99%

Serine protease acylation proceeds with a subtle re-orientation of the histidine ring at the tetrahedral intermediate

Zhou

Zhang

2011

Chem. Commun.

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“…However, theoretical calculations on the active site of chymotrypsin have predicted a serine pK a of *8 [24] and there is precedent for large perturbations of the pK a of amino acid residues in enzymes [25,26]. In view of the recently accepted hydrogen bonding (HB) network of Asp102, His57, Ser195 in the active site of chymotrypsin [18] as shown in Scheme 2, and in the absence of any significant microenvironmental effect on pK a , one can readily predict that the pK a of Ser195 should be higher than 13 (the expected pK a value for free serine amino acid).…”

Section: The Pk a Of His57 And Ser195 Of Serine Proteasesmentioning

confidence: 99%

Can a Typical Protein Assist the Rate of its Own Aqueous Cleavage?

Khan

2010

Progress in Reaction Kinetics and Mechanism

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Implications of k un and k H for the aqueous cleavage of proteins 153 9.2 Mechanistic aspects of aqueous un-, H þ -and HO À -catalysed cleavage of the imide bond 155 9.2.1 The mechanism of the nucleophilic reaction of water with imide 158 9.2.2 The mechanism of H þ -catalysed hydrolysis of imide bond 160 9.3 Aqueous pH -independent cleavage of amide bond of diamides (5, 15 -18) 160 10. CONCLUSIONS 161 11. ACKNOWLEDGEMENTS 161 12. REFERENCES 162 132 Mohammad Niyaz Khan www.prkm.co.uk ABSTRACTA recent finding of a large rate enhancement in the intramolecular secondary amide group-assisted cleavage of an adjacent tertiary amide bond predicts the possibility of the cleavage of the peptide bond of a protein through a similar reaction mechanism. Based upon enzymatic partial model reactions, the usual proton-switch mechanism has been suggested for the acylation step of the chymotrypsin -catalysed cleavage of the peptide bond which does not favour a His57-shift mechanism -an essential component of the classical charge relay mechanism. Also, the proton-switch mechanism does not necessarily require the two proton-transfer of the classical charge relay mechanism. The unique structural feature of the imidazole moiety of His57 is concluded to be essential in decreasing the rate of collapse of the proposed reactive tetrahedral intermediate back to the reactants. The proposed intramolecular intimate ion-pair formation between anionic Asp102 and cationic His57 is attributed to the energetically preferred location of the proton at Nd 1 of the imidazole moiety of His57. Thus, the analysis described in this review does not favour the necessary requirements of a two proton-transfer and His57-shift as proposed in the classical charge relay mechanism as well as the relatively recently proposed His57-flip mechanism.KEYWORDS: hydrolysis of amide and imide bond, intramolecular assistance, implication for peptide hydrolysis, enzyme-catalysed cleavage of peptide bond, proton-switch mechanism Prog React Kinet Mech 35: 131 -165.

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Mechanism of the serine protease reaction. Stereoelectronic, structural, and kinetic considerations as guidelines to deduce reaction paths

Cited by 31 publications

References 28 publications

Proteolytically stable peptides by incorporation of α-Tfm amino acids

Proteolytically stable peptides by incorporation of α-Tfm amino acids

Serine protease acylation proceeds with a subtle re-orientation of the histidine ring at the tetrahedral intermediate

Can a Typical Protein Assist the Rate of its Own Aqueous Cleavage?

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