Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release
5′-aminolevulinate synthase (ALAS) catalyzes the first step in heme biosynthesis, generating 5′-aminolevulinate from glycine and succinyl-CoA. Inherited frameshift indel mutations of human erythroid-specific isozyme ALAS2, within a C-terminal (Ct) extension of its catalytic core that is only present...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Springer Nature
2020
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| _version_ | 1797055112010530816 |
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| author | Bailey, HJ Arruda Bezerra, G Marcero, JR Padhi, S Foster, WR Rembeza, E Roy, A Bishop, DF Desnick, RJ Bulusu, G Dailey, HA Yue, WW |
| author_facet | Bailey, HJ Arruda Bezerra, G Marcero, JR Padhi, S Foster, WR Rembeza, E Roy, A Bishop, DF Desnick, RJ Bulusu, G Dailey, HA Yue, WW |
| author_sort | Bailey, HJ |
| collection | OXFORD |
| description | 5′-aminolevulinate synthase (ALAS) catalyzes the first step in heme biosynthesis, generating 5′-aminolevulinate from glycine and succinyl-CoA. Inherited frameshift indel mutations of human erythroid-specific isozyme ALAS2, within a C-terminal (Ct) extension of its catalytic core that is only present in higher eukaryotes, lead to gain-of-function X-linked protoporphyria (XLP). Here, we report the human ALAS2 crystal structure, revealing that its Ct-extension folds onto the catalytic core, sits atop the active site, and precludes binding of substrate succinyl-CoA. The Ct-extension is therefore an autoinhibitory element that must re-orient during catalysis, as supported by molecular dynamics simulations. Our data explain how Ct deletions in XLP alleviate autoinhibition and increase enzyme activity. Crystallography-based fragment screening reveals a binding hotspot around the Ct-extension, where fragments interfere with the Ct conformational dynamics and inhibit ALAS2 activity. These fragments represent a starting point to develop ALAS2 inhibitors as substrate reduction therapy for porphyria disorders that accumulate toxic heme intermediates. |
| first_indexed | 2024-03-06T19:06:41Z |
| format | Journal article |
| id | oxford-uuid:1562458e-407a-4797-b557-a1e24f56837d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:06:41Z |
| publishDate | 2020 |
| publisher | Springer Nature |
| record_format | dspace |
| spelling | oxford-uuid:1562458e-407a-4797-b557-a1e24f56837d2022-03-26T10:25:21ZHuman aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product releaseJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1562458e-407a-4797-b557-a1e24f56837dEnglishSymplectic ElementsSpringer Nature2020Bailey, HJArruda Bezerra, GMarcero, JRPadhi, SFoster, WRRembeza, ERoy, ABishop, DFDesnick, RJBulusu, GDailey, HAYue, WW5′-aminolevulinate synthase (ALAS) catalyzes the first step in heme biosynthesis, generating 5′-aminolevulinate from glycine and succinyl-CoA. Inherited frameshift indel mutations of human erythroid-specific isozyme ALAS2, within a C-terminal (Ct) extension of its catalytic core that is only present in higher eukaryotes, lead to gain-of-function X-linked protoporphyria (XLP). Here, we report the human ALAS2 crystal structure, revealing that its Ct-extension folds onto the catalytic core, sits atop the active site, and precludes binding of substrate succinyl-CoA. The Ct-extension is therefore an autoinhibitory element that must re-orient during catalysis, as supported by molecular dynamics simulations. Our data explain how Ct deletions in XLP alleviate autoinhibition and increase enzyme activity. Crystallography-based fragment screening reveals a binding hotspot around the Ct-extension, where fragments interfere with the Ct conformational dynamics and inhibit ALAS2 activity. These fragments represent a starting point to develop ALAS2 inhibitors as substrate reduction therapy for porphyria disorders that accumulate toxic heme intermediates. |
| spellingShingle | Bailey, HJ Arruda Bezerra, G Marcero, JR Padhi, S Foster, WR Rembeza, E Roy, A Bishop, DF Desnick, RJ Bulusu, G Dailey, HA Yue, WW Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title | Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title_full | Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title_fullStr | Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title_full_unstemmed | Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title_short | Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release |
| title_sort | human aminolevulinate synthase structure reveals a eukaryotic specific autoinhibitory loop regulating substrate binding and product release |
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