Cargando…

Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate

[Image: see text] Polyhydroxyalkanoates (PHAs) are a family of biopolyesters that accumulate as carbon and energy storage compounds in a variety of micro-organisms. The marine purple photosynthetic bacterium Rhodovulum sulfidophilum is capable of synthesizing PHA. In this study, we cloned a gene enc...

Descripción completa

Detalles Bibliográficos
Autores principales: Higuchi-Takeuchi, Mieko, Motoda, Yoko, Kigawa, Takanori, Numata, Keiji
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2017
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044645/
https://www.ncbi.nlm.nih.gov/pubmed/30023736
http://dx.doi.org/10.1021/acsomega.7b00667
_version_ 1783339511643635712
author Higuchi-Takeuchi, Mieko
Motoda, Yoko
Kigawa, Takanori
Numata, Keiji
author_facet Higuchi-Takeuchi, Mieko
Motoda, Yoko
Kigawa, Takanori
Numata, Keiji
author_sort Higuchi-Takeuchi, Mieko
collection PubMed
description [Image: see text] Polyhydroxyalkanoates (PHAs) are a family of biopolyesters that accumulate as carbon and energy storage compounds in a variety of micro-organisms. The marine purple photosynthetic bacterium Rhodovulum sulfidophilum is capable of synthesizing PHA. In this study, we cloned a gene encoding a class I PHA synthase from R. sulfidophilum (phaC(Rs)) and synthesized PhaC(Rs) using a cell-free protein expression system. The specific activity of PhaC(Rs) increased linearly as the (R)-3-hydroxybutyryl-coenzyme A (3HB-CoA) concentration increased and never reached a plateau, even at 3.75 mM 3HB-CoA, suggesting that PhaC(Rs) was not saturated because of low substrate affinity. Size exclusion chromatography and native polyacrylamide gel electrophoresis analyses revealed that PhaC(Rs) exists predominantly as an active dimer even in the absence of 3HB-CoA, unlike previously characterized PhaCs. The linear relationship between the PhaC(Rs) activity and 3HB-CoA concentrations could result from a low substrate affinity as well as the absence of a rate-limiting step during PHA polymerization because of the existence of predominantly active dimers.
format Online
Article
Text
id pubmed-6044645
institution National Center for Biotechnology Information
language English
publishDate 2017
publisher American Chemical Society
record_format MEDLINE/PubMed
spelling pubmed-60446452018-07-16 Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate Higuchi-Takeuchi, Mieko Motoda, Yoko Kigawa, Takanori Numata, Keiji ACS Omega [Image: see text] Polyhydroxyalkanoates (PHAs) are a family of biopolyesters that accumulate as carbon and energy storage compounds in a variety of micro-organisms. The marine purple photosynthetic bacterium Rhodovulum sulfidophilum is capable of synthesizing PHA. In this study, we cloned a gene encoding a class I PHA synthase from R. sulfidophilum (phaC(Rs)) and synthesized PhaC(Rs) using a cell-free protein expression system. The specific activity of PhaC(Rs) increased linearly as the (R)-3-hydroxybutyryl-coenzyme A (3HB-CoA) concentration increased and never reached a plateau, even at 3.75 mM 3HB-CoA, suggesting that PhaC(Rs) was not saturated because of low substrate affinity. Size exclusion chromatography and native polyacrylamide gel electrophoresis analyses revealed that PhaC(Rs) exists predominantly as an active dimer even in the absence of 3HB-CoA, unlike previously characterized PhaCs. The linear relationship between the PhaC(Rs) activity and 3HB-CoA concentrations could result from a low substrate affinity as well as the absence of a rate-limiting step during PHA polymerization because of the existence of predominantly active dimers. American Chemical Society 2017-08-29 /pmc/articles/PMC6044645/ /pubmed/30023736 http://dx.doi.org/10.1021/acsomega.7b00667 Text en Copyright © 2017 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Higuchi-Takeuchi, Mieko
Motoda, Yoko
Kigawa, Takanori
Numata, Keiji
Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title_full Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title_fullStr Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title_full_unstemmed Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title_short Class I Polyhydroxyalkanoate Synthase from the Purple Photosynthetic Bacterium Rhodovulum sulfidophilum Predominantly Exists as a Functional Dimer in the Absence of a Substrate
title_sort class i polyhydroxyalkanoate synthase from the purple photosynthetic bacterium rhodovulum sulfidophilum predominantly exists as a functional dimer in the absence of a substrate
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044645/
https://www.ncbi.nlm.nih.gov/pubmed/30023736
http://dx.doi.org/10.1021/acsomega.7b00667
work_keys_str_mv AT higuchitakeuchimieko classipolyhydroxyalkanoatesynthasefromthepurplephotosyntheticbacteriumrhodovulumsulfidophilumpredominantlyexistsasafunctionaldimerintheabsenceofasubstrate
AT motodayoko classipolyhydroxyalkanoatesynthasefromthepurplephotosyntheticbacteriumrhodovulumsulfidophilumpredominantlyexistsasafunctionaldimerintheabsenceofasubstrate
AT kigawatakanori classipolyhydroxyalkanoatesynthasefromthepurplephotosyntheticbacteriumrhodovulumsulfidophilumpredominantlyexistsasafunctionaldimerintheabsenceofasubstrate
AT numatakeiji classipolyhydroxyalkanoatesynthasefromthepurplephotosyntheticbacteriumrhodovulumsulfidophilumpredominantlyexistsasafunctionaldimerintheabsenceofasubstrate