Characterization of a secreted aminopeptidase of M28 family from B. fragilis and its possible role in protein metabolism in the gut.

Autor: Kulkarni BS; Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Life Sciences Department, Homi Bhabha National Institute, Mumbai 400094, India., Makde RD; Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India; Life Sciences Department, Homi Bhabha National Institute, Mumbai 400094, India., Jamdar SN; Food Technology Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Life Sciences Department, Homi Bhabha National Institute, Mumbai 400094, India. Electronic address: snjam@barc.gov.in.
Jazyk: angličtina
Zdroj: Biochimica et biophysica acta. General subjects [Biochim Biophys Acta Gen Subj] 2024 May; Vol. 1868 (5), pp. 130598. Date of Electronic Publication: 2024 Mar 16.
DOI: 10.1016/j.bbagen.2024.130598
Abstrakt: Products of microbial protein metabolism in the gut can influence the health of the host in many ways. Members of the Bacteriodales, major commensals of the human colon have been associated with long-term intake of high-protein diets. Undigested proteins or peptides that reach the colon can be hydrolyzed by extra-cellular proteases found in some Bacteroides species into amino acids and peptides which can be further catabolized. In this communication, we have characterized one such secreted aminopeptidase (BfAP) from Bacteroides fragilis belonging to the M28 family which is capable of degrading peptides released from soybean protein after predigestion in the small intestine. The BfAP enzyme was cloned, expressed in E. coli, and purified to homogeneity. It is a metallopeptidase requiring Co 2+ ion for optimum activity at 55 °C and pH 8 and preferentially cleaves neutral aliphatic (Met/Leu) and positively charged (Arg/Lys) amino acids from the N-terminus of peptides. It showed high specificity for long peptides as well as proteins like β-casein. Structural analysis of BfAP and its orthologues using AlphaFold2 reveal a shared highly conserved M28 domain, but vary with respect to their N-terminal region with some of them possessing an additional cap domain which may be important for regulation of substrate binding. Although BfAP lacks the typical cap domain, it shows small extensions that can form a loop adjacent to the proposed active site and may affect substrate binding. We suggest that this secreted enzyme may play an important role in protein metabolism in the colon where Bacteroides species are abundant.
Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest with the contents of this article.
(Copyright © 2023. Published by Elsevier B.V.)
Databáze: MEDLINE
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