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A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein

Saccharomyces cerevisiae acyl carrier protein (ScACP) is a component of the large fungal fatty acid synthase I (FAS I) complex. ScACP comprises two subdomains: a conserved ACP domain that shares extensive structural homology with other ACPs and a unique structural domain. Unlike the metazoan type I...

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Autores principales: Garima, Prem, Rashima, Yadav, Usha, Sundd, Monica
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8683515/
https://www.ncbi.nlm.nih.gov/pubmed/34767798
http://dx.doi.org/10.1016/j.jbc.2021.101394
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author Garima
Prem, Rashima
Yadav, Usha
Sundd, Monica
author_facet Garima
Prem, Rashima
Yadav, Usha
Sundd, Monica
author_sort Garima
collection PubMed
description Saccharomyces cerevisiae acyl carrier protein (ScACP) is a component of the large fungal fatty acid synthase I (FAS I) complex. ScACP comprises two subdomains: a conserved ACP domain that shares extensive structural homology with other ACPs and a unique structural domain. Unlike the metazoan type I ACP that does not sequester the acyl chain, ScACP can partially sequester the growing acyl chain within its hydrophobic core by a mechanism that remains elusive. Our studies on the acyl-ScACP intermediates disclose a unique (188)GX(2)GX(3)G(195) sequence in helix II important for ACP function. Complete loss of sequestration was observed upon mutation of the three glycines in this sequence to valine (G188V/G191V/G195V), while G191V and G188V/G191V double mutants displayed a faster rate of acyl chain hydrolysis. Likewise, mutation of Thr216 to Ala altered the size of the hydrophobic cavity, resulting in loss of C(12)- chain sequestration. Combining NMR studies with insights from the crystal structure, we show that three glycines in helix II and a threonine in helix IV favor conformational change, which in turn generate space for acyl chain sequestration. Furthermore, we identified the primary hydrophobic cavity of ScACP, present between the carboxyl end of helix II and IV. The opening of the cavity lies between the second and third turns of helix II and loop II. Overall, the study highlights a novel role of the GX(2)GX(3)G motif in regulating acyl chain sequestration, vital for ScACP function.
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spelling pubmed-86835152021-12-30 A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein Garima Prem, Rashima Yadav, Usha Sundd, Monica J Biol Chem Research Article Saccharomyces cerevisiae acyl carrier protein (ScACP) is a component of the large fungal fatty acid synthase I (FAS I) complex. ScACP comprises two subdomains: a conserved ACP domain that shares extensive structural homology with other ACPs and a unique structural domain. Unlike the metazoan type I ACP that does not sequester the acyl chain, ScACP can partially sequester the growing acyl chain within its hydrophobic core by a mechanism that remains elusive. Our studies on the acyl-ScACP intermediates disclose a unique (188)GX(2)GX(3)G(195) sequence in helix II important for ACP function. Complete loss of sequestration was observed upon mutation of the three glycines in this sequence to valine (G188V/G191V/G195V), while G191V and G188V/G191V double mutants displayed a faster rate of acyl chain hydrolysis. Likewise, mutation of Thr216 to Ala altered the size of the hydrophobic cavity, resulting in loss of C(12)- chain sequestration. Combining NMR studies with insights from the crystal structure, we show that three glycines in helix II and a threonine in helix IV favor conformational change, which in turn generate space for acyl chain sequestration. Furthermore, we identified the primary hydrophobic cavity of ScACP, present between the carboxyl end of helix II and IV. The opening of the cavity lies between the second and third turns of helix II and loop II. Overall, the study highlights a novel role of the GX(2)GX(3)G motif in regulating acyl chain sequestration, vital for ScACP function. American Society for Biochemistry and Molecular Biology 2021-11-09 /pmc/articles/PMC8683515/ /pubmed/34767798 http://dx.doi.org/10.1016/j.jbc.2021.101394 Text en © 2021 The Authors https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Research Article
Garima
Prem, Rashima
Yadav, Usha
Sundd, Monica
A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title_full A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title_fullStr A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title_full_unstemmed A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title_short A GX(2)GX(3)G motif facilitates acyl chain sequestration by Saccharomyces cerevisiae acyl carrier protein
title_sort gx(2)gx(3)g motif facilitates acyl chain sequestration by saccharomyces cerevisiae acyl carrier protein
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8683515/
https://www.ncbi.nlm.nih.gov/pubmed/34767798
http://dx.doi.org/10.1016/j.jbc.2021.101394
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