The properties and potential metabolic role of glucokinase in halotolerant obligate methanotroph Methylomicrobium alcaliphilum 20Z
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- 作者：Ildar I. Mustakhimov ; Olga N. Rozova ; Natalia P. Solntseva…
- 关键词：Methanotrophic bacteria ; Methylomicrobium alcaliphilum 20Z ; Glucokinase ; Sucrose ; Glycogen
- 刊名：Antonie van Leeuwenhoek
- 出版年：2017
- 出版时间：March 2017
- 年：2017
- 卷：110
- 期：3
- 页码：375-386
- 全文大小：
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Microbiology; Medical Microbiology; Plant Sciences; Soil Science & Conservation;
- 出版者：Springer International Publishing
- ISSN：1572-9699
- 卷排序：110
文摘
Aerobic bacteria utilizing methane as the carbon and energy source do not use sugars as growth substrates but possess the gene coding for glucokinase (Glk), an enzyme converting glucose into glucose 6-phosphate. Here we demonstrate the functionality and properties of Glk from an obligate methanotroph Methylomicrobium alcaliphilum 20Z. The recombinant Glk obtained by heterologous expression in Escherichia coli was found to be close in biochemical properties to other prokaryotic Glks. The homodimeric enzyme (2 × 35 kDa) catalyzed ATP-dependent phosphorylation of glucose and glucosamine with nearly equal activity, being inhibited by ADP (Ki = 2.34 mM) but not affected by glucose 6-phosphate. Chromosomal deletion of the glk gene resulted in a loss of Glk activity and retardation of growth as well as in a decrease of intracellular glycogen content. Inactivation of the genes encoding sucrose phosphate synthase or amylosucrase, the enzymes involved in glycogen biosynthesis via sucrose as intermediate, did not prevent glycogen accumulation. In silico analysis revealed glk orthologs predominantly in methanotrophs harboring glycogen synthase genes. The data obtained suggested that Glk is implicated in the regulation of glycogen biosynthesis/degradation in an obligate methanotroph.