AI Article Synopsis

  • Hydroxysteroid dehydrogenases (HSDHs) are essential for bile acid metabolism and can be engineered for medical applications.
  • Mutations at the cofactor binding site of HSDH St-2-2 led to significantly increased catalytic activity and altered substrate preference in engineered bacteria.
  • Structural analysis suggests that changing specific residues improves both the enzyme's performance and thermal stability by enhancing interactions within its active site.

Article Abstract

Hydroxysteroid dehydrogenases (HSDHs) are crucial for bile acid metabolism and influence the size of the bile acid pool and gut microbiota composition. HSDHs with high activity, thermostability, and substrate selectivity are the basis for constructing engineered bacteria for disease treatment. In this study, we designed mutations at the cofactor binding site involving Thr15 and Arg16 residues of HSDH St-2-2. The T15A, R16A, and R16Q mutants exhibited 7.85-, 2.50-, and 4.35-fold higher catalytic activity than the wild type, respectively, while also displaying an altered substrate preference (from taurocholic acid (TCA) to taurochenodeoxycholic acid (TCDCA)). These mutants showed lower K and higher k values, indicating stronger binding to the substrate and resulting in 3190-, 3123-, and 3093-fold higher k/K values for TCDCA oxidation. Furthermore, the T values of the T15A, R16A, and R16Q mutants were found to increase by 4.3 °C, 6.0 °C, and 7.0 °C, respectively. Molecular structure analysis indicated that reshaped internal hydrogens and surface mutations could improve catalytic activity and thermostability, and altered interactions among the catalytic triad, cofactor binding sites, and substrates could change substrate preference. This work provides valuable insights into modifying substrate preference as well as enhancing the catalytic activity and thermostability of HSDHs by targeting the cofactor binding site.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijbiomac.2023.128847DOI Listing

Publication Analysis

Top Keywords

cofactor binding
16
catalytic activity
16
activity thermostability
16
substrate preference
16
binding site
12
bile acid
8
t15a r16a
8
r16a r16q
8
r16q mutants
8
substrate
6

Similar Publications

Background: All chemical forms of energy and oxygen on Earth are generated via photosynthesis where light energy is converted into redox energy by two photosystems (PS I and PS II). There is an increasing number of PS I 3D structures deposited in the Protein Data Bank (PDB). The Triangular Spatial Relationship (TSR)-based algorithm converts 3D structures into integers (TSR keys).

View Article and Find Full Text PDF

Protein citrullination modification plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA), and anti-citrullinated protein antibodies (ACPAs) are extensively employed for clinical diagnosis of RA. However, there remains limited understanding regarding specific citrullinated proteins and their implications in the progression of RA. In this study, we screen and verify insulin-like growth factor-2 mRNA binding protein 1 (IGF2BP1) as a novel citrullinated protein with significantly elevated citrullinated level in RA.

View Article and Find Full Text PDF

Structural determinants of oxygen resistance and Zn-mediated stability of the [FeFe]-hydrogenase from .

Proc Natl Acad Sci U S A

January 2025

Laboratory for Protein Crystallography, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.

[FeFe]-hydrogenases catalyze the reversible two-electron reduction of two protons to molecular hydrogen. Although these enzymes are among the most efficient H-converting biocatalysts in nature, their catalytic cofactor (termed H-cluster) is irreversibly destroyed upon contact with dioxygen. The [FeFe]-hydrogenase CbA5H from has a unique mechanism to protect the H-cluster from oxygen-induced degradation.

View Article and Find Full Text PDF

( ) is the world's most deadly infectious pathogen and new drugs are urgently required to combat the emergence of multi-(MDR) and extensively-(XDR) drug resistant strains. The bacterium specifically upregulates sterol uptake pathways in infected macrophages and the metabolism of host-derived cholesterol is essential for long-term survival Here, we report the development of antitubercular small molecules that inhibit the cholesterol oxidases CYP125 and CYP142, which catalyze the initial step of cholesterol metabolism. An efficient biophysical fragment screen was used to characterize the structure-activity relationships of CYP125 and CYP142, and identify a non-azole small molecule that can bind to the heme cofactor of both enzymes.

View Article and Find Full Text PDF

The [4Fe-4S] cluster is an important cofactor of the base excision repair (BER) adenine DNA glycosylase MutY to prevent mutations associated with 8-oxoguanine (OG). Several MutYs lacking the [4Fe-4S] cofactor have been identified. Phylogenetic analysis shows that clusterless MutYs are distributed in two clades suggesting cofactor loss in two independent evolutionary events.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!