Synthesis, Purification, and Properties of a Semisynthetic Ribonuclease S Incorporating 4-Fluoro-l-histidine at Position 12
Year: 1974
Type: article
Abstract: The NH2-terminal pentadecapeptide of ribonuclease was synthesized with 4-fluoro-l-histidine (4-F-His) in place of the naturally occurring histidine at position 12. This peptide, [4-F-His 12]synthetic-(1-15), serves as an active site analogue of the native NH2-terminal eicosapeptide, RNase-S-(1-20), in that it forms a stable, noncovalent complex with the native ribonuclease fragment of residues 21 through 124, RNase-S-(21-124). A functional purification scheme has been used to prepare purified synthetic peptide in two steps. Purified semisynthetic ribonuclease S analogue complex was obtained by sulfoethyl-Sephadex chromatography of a mixture of crude, solid phase-derived peptide and native RNase-S-(21-124). Isolated [4-F-His 12]synthetic-(1-15) peptide was obtained from the purified complex after dissociation in 50 % acetic acid and gel permeation chromatography. The substitution of fluorine in the 4 position of the imidazole ring of histidine 12 does not disrupt the association of the synthetic peptide to native RNase-S-(21-124) as demonstrated by the binding constant measured in competition with native RNase-S-(1-20). Several other conformational properties of the analogue complex also are similar to those of the native RNase-S complex. However, the complex of [4-F-His 12]-synthetic-(1-15) and RNase-S-(21-124) is devoid of catalytic activity, a result attributed to the perturbation in the acid dissociation constant of the imidazole side chain by fluorine substitution.
Source: Journal of Biological Chemistry
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1614309138