Dataset Information

The structure of a family GH25 lysozyme from Aspergillus fumigatus.

ABSTRACT: Lysins are important biomolecules which cleave the bacterial cell-wall polymer peptidoglycan. They are finding increasing commercial and medical application. In order to gain an insight into the mechanism by which these enzymes operate, the X-ray structure of a CAZy family GH25 ;lysozyme' from Aspergillus fumigatus was determined. This is the first fungal structure from the family and reveals a modified alpha/beta-barrel-like fold in which an eight-stranded beta-barrel is flanked by three alpha-helices. The active site lies toward the bottom of a negatively charged pocket and its layout has much in common with other solved members of the GH25 and related GH families. A conserved active-site DXE motif may be implicated in catalysis, lending further weight to the argument that this glycoside hydrolase family operates via a ;substrate-assisted' catalytic mechanism.

SUBMITTER: Korczynska JE

PROVIDER: S-EPMC2935209 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The structure of a family GH25 lysozyme from Aspergillus fumigatus.

Korczynska Justyna E JE Danielsen Steffen S Schagerlöf Ulrika U Turkenburg Johan P JP Davies Gideon J GJ Wilson Keith S KS Taylor Edward J EJ

Acta crystallographica. Section F, Structural biology and crystallization communications 20100821 Pt 9

Lysins are important biomolecules which cleave the bacterial cell-wall polymer peptidoglycan. They are finding increasing commercial and medical application. In order to gain an insight into the mechanism by which these enzymes operate, the X-ray structure of a CAZy family GH25 ;lysozyme' from Aspergillus fumigatus was determined. This is the first fungal structure from the family and reveals a modified alpha/beta-barrel-like fold in which an eight-stranded beta-barrel is flanked by three alpha- ...[more]

PMID: 20823508

Similar Datasets

Project description:UnlabelledErgosterol is a major and specific component of the fungal plasma membrane, and thus, the cytochrome P450 enzymes (Erg proteins) that catalyze ergosterol synthesis have been selected as valuable targets of azole antifungals. However, the opportunistic pathogen Aspergillus fumigatus has developed worldwide resistance to azoles largely through mutations in the cytochrome P450 enzyme Cyp51 (Erg11). In this study, we demonstrate that a cytochrome b5-like heme-binding damage resistance protein (Dap) family, comprised of DapA, DapB, and DapC, coordinately regulates the functionality of cytochrome P450 enzymes Erg5 and Erg11 and oppositely affects susceptibility to azoles. The expression of all three genes is induced in an azole concentration-dependent way, and the decreased susceptibility to azoles requires DapA stabilization of cytochrome P450 protein activity. In contrast, overexpression of DapB and DapC causes dysfunction of Erg5 and Erg11, resulting in abnormal accumulation of sterol intermediates and further accentuating the sensitivity of ΔdapA strains to azoles. The results of exogenous-hemin rescue and heme-binding-site mutagenesis experiments demonstrate that the heme binding of DapA contributes the decreased azole susceptibility, while DapB and -C are capable of reducing the activities of Erg5 and Erg11 through depletion of heme. In vivo data demonstrate that inactivated DapA combined with activated DapB yields an A. fumigatus mutant that is easily treatable with azoles in an immunocompromised mouse model of invasive pulmonary aspergillosis. Compared to the single Dap proteins found in Saccharomyces cerevisiae and Schizosaccharomyces pombe, we suggest that this complex Dap family regulatory system emerged during the evolution of fungi as an adaptive means to regulate ergosterol synthesis in response to environmental stimuli.ImportanceKnowledge of the ergosterol biosynthesis route in fungal pathogens is useful in the design of new antifungal drugs and could aid in the study of antifungal-drug resistance mechanisms. In this study, we demonstrate that three cytochrome b5-like Dap proteins coordinately regulate the azole resistance and ergosterol biosynthesis catalyzed by cytochrome P450 proteins. Our new insights into the Dap regulatory system in fungal pathogens may have broad therapeutic ramifications beyond their usefulness for classic azole antifungals. Moreover, our elucidation of the molecular mechanism of Dap regulation of cytochrome P450 protein functionality through heme-binding activity may extend beyond the Kingdom Fungi with applicability toward Dap protein regulation of mammalian sterol synthesis.

Dataset Information

The structure of a family GH25 lysozyme from Aspergillus fumigatus.

Publications

The structure of a family GH25 lysozyme from Aspergillus fumigatus.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets