Structurally divergent lysophosphatidic acid acyltransferases with high selectivity for saturated medium chain fatty acids from Cuphea seeds

Hae Jin Kim, Jillian E. Silva, Umidjon Iskandarov, Mariette Andersson, Rebecca E. Cahoon, Keithanne Mockaitis, Edgar B. Cahoon

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn-2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Δ9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn-2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed-specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed-specific LPAT from the bacterial-type class B. The activities of these enzymes were characterized in Camelina sativa by seed-specific co-expression with cDNAs for various Cuphea FatB acyl-acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium-chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10:0 fatty acids in the Camelina sativa TAG sn-2 position, indicating a 10:0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14:0 at the sn-2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities. Significance Statement Typical lysophosphatidic acid acyltransferases (LPATs) have strict specificity for C18 fatty acids with Δ9 unsaturation. Here we analyzed the transcriptomes of developing seeds of Cuphea species known to accumulate saturated C8 and C10 fatty acids, and thereby identified seed-specific acyltransferases with in vivo selectivity for saturated (10:0) fatty acids. These LPATs provide tools for understanding the structural basis for LPAT substrate specificity and should facilitate the engineering of different oil functionalities.

Original languageEnglish (US)
Pages (from-to)1021-1033
Number of pages13
JournalPlant Journal
Volume84
Issue number5
DOIs
StatePublished - Dec 1 2015

Fingerprint

Cuphea
acyltransferases
medium chain fatty acids
saturated fatty acids
Seeds
Fatty Acids
acids
seeds
Triglycerides
triacylglycerols
fatty acids
Complementary DNA
Substrate Specificity
substrate specificity
Oils
Camelina sativa
2-acylglycerophosphate acyltransferase
Acyl Carrier Protein
Cuphea viscosissima
Acyltransferases

Keywords

  • Camelina sativa
  • Cuphea
  • Cuphea avigera var. pulcherrima
  • Cuphea viscosissima
  • acyl CoA
  • fatty acid
  • lysophosphatidic acid acyltransferase
  • medium chain fatty acid
  • oilseed
  • triacylglycerol

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

Cite this

Structurally divergent lysophosphatidic acid acyltransferases with high selectivity for saturated medium chain fatty acids from Cuphea seeds. / Kim, Hae Jin; Silva, Jillian E.; Iskandarov, Umidjon; Andersson, Mariette; Cahoon, Rebecca E.; Mockaitis, Keithanne; Cahoon, Edgar B.

In: Plant Journal, Vol. 84, No. 5, 01.12.2015, p. 1021-1033.

Research output: Contribution to journalArticle

Kim, Hae Jin ; Silva, Jillian E. ; Iskandarov, Umidjon ; Andersson, Mariette ; Cahoon, Rebecca E. ; Mockaitis, Keithanne ; Cahoon, Edgar B. / Structurally divergent lysophosphatidic acid acyltransferases with high selectivity for saturated medium chain fatty acids from Cuphea seeds. In: Plant Journal. 2015 ; Vol. 84, No. 5. pp. 1021-1033.
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abstract = "Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn-2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Δ9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn-2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed-specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed-specific LPAT from the bacterial-type class B. The activities of these enzymes were characterized in Camelina sativa by seed-specific co-expression with cDNAs for various Cuphea FatB acyl-acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium-chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10:0 fatty acids in the Camelina sativa TAG sn-2 position, indicating a 10:0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14:0 at the sn-2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities. Significance Statement Typical lysophosphatidic acid acyltransferases (LPATs) have strict specificity for C18 fatty acids with Δ9 unsaturation. Here we analyzed the transcriptomes of developing seeds of Cuphea species known to accumulate saturated C8 and C10 fatty acids, and thereby identified seed-specific acyltransferases with in vivo selectivity for saturated (10:0) fatty acids. These LPATs provide tools for understanding the structural basis for LPAT substrate specificity and should facilitate the engineering of different oil functionalities.",
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AU - Kim, Hae Jin

AU - Silva, Jillian E.

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AU - Andersson, Mariette

AU - Cahoon, Rebecca E.

AU - Mockaitis, Keithanne

AU - Cahoon, Edgar B.

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N2 - Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn-2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Δ9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn-2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed-specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed-specific LPAT from the bacterial-type class B. The activities of these enzymes were characterized in Camelina sativa by seed-specific co-expression with cDNAs for various Cuphea FatB acyl-acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium-chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10:0 fatty acids in the Camelina sativa TAG sn-2 position, indicating a 10:0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14:0 at the sn-2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities. Significance Statement Typical lysophosphatidic acid acyltransferases (LPATs) have strict specificity for C18 fatty acids with Δ9 unsaturation. Here we analyzed the transcriptomes of developing seeds of Cuphea species known to accumulate saturated C8 and C10 fatty acids, and thereby identified seed-specific acyltransferases with in vivo selectivity for saturated (10:0) fatty acids. These LPATs provide tools for understanding the structural basis for LPAT substrate specificity and should facilitate the engineering of different oil functionalities.

AB - Lysophosphatidic acid acyltransferase (LPAT) catalyzes acylation of the sn-2 position on lysophosphatidic acid by an acyl CoA substrate to produce the phosphatidic acid precursor of polar glycerolipids and triacylglycerols (TAGs). In the case of TAGs, this reaction is typically catalyzed by an LPAT2 from microsomal LPAT class A that has high specificity for C18 fatty acids containing Δ9 unsaturation. Because of this specificity, the occurrence of saturated fatty acids in the TAG sn-2 position is infrequent in seed oils. To identify LPATs with variant substrate specificities, deep transcriptomic mining was performed on seeds of two Cuphea species producing TAGs that are highly enriched in saturated C8 and C10 fatty acids. From these analyses, cDNAs for seven previously unreported LPATs were identified, including cDNAs from Cuphea viscosissima (CvLPAT2) and Cuphea avigera var. pulcherrima (CpuLPAT2a) encoding microsomal, seed-specific class A LPAT2s and a cDNA from C. avigera var. pulcherrima (CpuLPATB) encoding a microsomal, seed-specific LPAT from the bacterial-type class B. The activities of these enzymes were characterized in Camelina sativa by seed-specific co-expression with cDNAs for various Cuphea FatB acyl-acyl carrier protein thioesterases (FatB) that produce a variety of saturated medium-chain fatty acids. CvLPAT2 and CpuLPAT2a expression resulted in accumulation of 10:0 fatty acids in the Camelina sativa TAG sn-2 position, indicating a 10:0 CoA specificity that has not been previously described for plant LPATs. CpuLPATB expression generated TAGs with 14:0 at the sn-2 position, but not 10:0. Identification of these LPATs provides tools for understanding the structural basis of LPAT substrate specificity and for generating altered oil functionalities. Significance Statement Typical lysophosphatidic acid acyltransferases (LPATs) have strict specificity for C18 fatty acids with Δ9 unsaturation. Here we analyzed the transcriptomes of developing seeds of Cuphea species known to accumulate saturated C8 and C10 fatty acids, and thereby identified seed-specific acyltransferases with in vivo selectivity for saturated (10:0) fatty acids. These LPATs provide tools for understanding the structural basis for LPAT substrate specificity and should facilitate the engineering of different oil functionalities.

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KW - Cuphea viscosissima

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KW - lysophosphatidic acid acyltransferase

KW - medium chain fatty acid

KW - oilseed

KW - triacylglycerol

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