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Gurung MK, Altermark B, Helland R, Smalås AO, Ræder ILU. Features and structure of a cold active N-acetylneuraminate lyase. PLoS One 2019; 14:e0217713. [PMID: 31185017 PMCID: PMC6559660 DOI: 10.1371/journal.pone.0217713] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/16/2019] [Indexed: 11/23/2022] Open
Abstract
N-acetylneuraminate lyases (NALs) are enzymes that catalyze the reversible cleavage and synthesis of sialic acids. They are therefore commonly used for the production of these high-value sugars. This study presents the recombinant production, together with biochemical and structural data, of the NAL from the psychrophilic bacterium Aliivibrio salmonicida LFI1238 (AsNAL). Our characterization shows that AsNAL possesses high activity and stability at alkaline pH. We confirm that these properties allow for the use in a one-pot reaction at alkaline pH for the synthesis of N-acetylneuraminic acid (Neu5Ac, the most common sialic acid) from the inexpensive precursor N-acetylglucosamine. We also show that the enzyme has a cold active nature with an optimum temperature for Neu5Ac synthesis at 20°C. The equilibrium constant for the reaction was calculated at different temperatures, and the formation of Neu5Ac acid is favored at low temperatures, making the cold active enzyme a well-suited candidate for use in such exothermic reactions. The specific activity is high compared to the homologue from Escherichia coli at three tested temperatures, and the enzyme shows a higher catalytic efficiency and turnover number for cleavage at 37°C. Mutational studies reveal that amino acid residue Asn 168 is important for the high kcat. The crystal structure of AsNAL was solved to 1.65 Å resolution and reveals a compact, tetrameric protein similar to other NAL structures. The data presented provides a framework to guide further optimization of its application in sialic acid production and opens the possibility for further design of the enzyme.
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Affiliation(s)
- Man Kumari Gurung
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, UiT- The Arctic University of Norway, Tromsø, Norway
| | - Bjørn Altermark
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, UiT- The Arctic University of Norway, Tromsø, Norway
| | - Ronny Helland
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, UiT- The Arctic University of Norway, Tromsø, Norway
| | - Arne O. Smalås
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, UiT- The Arctic University of Norway, Tromsø, Norway
| | - Inger Lin U. Ræder
- The Norwegian Structural Biology Center (NorStruct), Department of Chemistry, UiT- The Arctic University of Norway, Tromsø, Norway
- * E-mail:
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Zagorec M, Champomier-Vergès MC. Lactobacillus sakei: A Starter for Sausage Fermentation, a Protective Culture for Meat Products. Microorganisms 2017; 5:microorganisms5030056. [PMID: 28878171 PMCID: PMC5620647 DOI: 10.3390/microorganisms5030056] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/29/2017] [Accepted: 09/05/2017] [Indexed: 12/28/2022] Open
Abstract
Among lactic acid bacteria of meat products, Lactobacillus sakei is certainly the most studied species due to its role in the fermentation of sausage and its prevalence during cold storage of raw meat products. Consequently, the physiology of this bacterium regarding functions involved in growth, survival, and metabolism during meat storage and processing are well known. This species exhibits a wide genomic diversity that can be observed when studying different strains and on which probably rely its multiple facets in meat products: starter, spoiler, or protective culture. The emerging exploration of the microbial ecology of meat products also revealed the multiplicity of bacterial interactions L. sakei has to face and their various consequences on microbial quality and safety at the end of storage.
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Hernández-García S, García-García MI, García-Carmona F. Improving the production, activity, and stability of CLEAs with diepoxides. Biotechnol Prog 2017; 33:1425-1429. [DOI: 10.1002/btpr.2505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 05/03/2017] [Indexed: 01/15/2023]
Affiliation(s)
- Samanta Hernández-García
- Faculty of Biology, Dept. of Biochemistry and Molecular Biology-A; Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia; Campus Espinardo, Murcia E-30100 Spain
| | - María Inmaculada García-García
- Faculty of Biology, Dept. of Biochemistry and Molecular Biology-A; Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia; Campus Espinardo, Murcia E-30100 Spain
| | - Francisco García-Carmona
- Faculty of Biology, Dept. of Biochemistry and Molecular Biology-A; Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia; Campus Espinardo, Murcia E-30100 Spain
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Martínez-Moñino AB, Zapata-Pérez R, García-Saura AG, Gil-Ortiz F, Pérez-Gilabert M, Sánchez-Ferrer Á. Characterization and mutational analysis of a nicotinamide mononucleotide deamidase from Agrobacterium tumefaciens showing high thermal stability and catalytic efficiency. PLoS One 2017; 12:e0174759. [PMID: 28388636 PMCID: PMC5384747 DOI: 10.1371/journal.pone.0174759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/15/2017] [Indexed: 01/07/2023] Open
Abstract
NAD+ has emerged as a crucial element in both bioenergetic and signaling pathways since it acts as a key regulator of cellular and organismal homeostasis. Among the enzymes involved in its recycling, nicotinamide mononucleotide (NMN) deamidase is one of the key players in the bacterial pyridine nucleotide cycle, where it catalyzes the conversion of NMN into nicotinic acid mononucleotide (NaMN), which is later converted to NAD+ in the Preiss-Handler pathway. The biochemical characteristics of bacterial NMN deamidases have been poorly studied, although they have been investigated in some firmicutes, gamma-proteobacteria and actinobacteria. In this study, we present the first characterization of an NMN deamidase from an alphaproteobacterium, Agrobacterium tumefaciens (AtCinA). The enzyme was active over a broad pH range, with an optimum at pH 7.5. Moreover, the enzyme was quite stable at neutral pH, maintaining 55% of its activity after 14 days. Surprisingly, AtCinA showed the highest optimal (80°C) and melting (85°C) temperatures described for an NMN deamidase. The above described characteristics, together with its high catalytic efficiency, make AtCinA a promising biocatalyst for the production of pure NaMN. In addition, six mutants (C32A, S48A, Y58F, Y58A, T105A and R145A) were designed to study their involvement in substrate binding, and two (S31A and K63A) to determine their contribution to the catalysis. However, only four mutants (C32A, S48A Y58F and T105A) showed activity, although with reduced catalytic efficiency. These results, combined with a thermal and structural analysis, reinforce the Ser/Lys catalytic dyad mechanism as the most plausible among those proposed.
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Affiliation(s)
- Ana Belén Martínez-Moñino
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
- Murcia Biomedical Research Institute (IMIB), Murcia, Spain
| | - Rubén Zapata-Pérez
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
- Murcia Biomedical Research Institute (IMIB), Murcia, Spain
| | - Antonio Ginés García-Saura
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
- Murcia Biomedical Research Institute (IMIB), Murcia, Spain
| | | | - Manuela Pérez-Gilabert
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
- Murcia Biomedical Research Institute (IMIB), Murcia, Spain
| | - Álvaro Sánchez-Ferrer
- Department of Biochemistry and Molecular Biology-A, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Campus Espinardo, E-30100 MURCIA, Spain
- Murcia Biomedical Research Institute (IMIB), Murcia, Spain
- * E-mail:
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