食品科学 ›› 2026, Vol. 47 ›› Issue (1): 142-155.doi: 10.7506/spkx1002-6630-20250620-150

• 食品工程 • 上一篇    

长双歧杆菌BBMN68中应答调节蛋白BBMN68_47的自调控及metK基因调控功能

陈书宜,宋静颐,宋晓东,张红星,谢远红,金君华   

  1. (1.北京农学院食品科学与工程学院,北京 102206;2.内蒙古蒙牛乳业(集团)股份有限公司,国家市场监管总局重点实验室(乳品质量数智监控技术),内蒙古 呼和浩特 011517)
  • 发布日期:2026-02-04

Autoregulation of Response Regulator BBMN68_47 and Its Regulatory Function on S-Adenosylmethionine Synthetase (metK) Gene in Bifidobacterium logum BBMN68

CHEN Shuyi, SONG Jingyi, SONG Xiaodong, ZHANG Hongxing, XIE Yuanhong, JIN Junhua   

  1. (1. Food Science and Engineering College, Beijing University of Agriculture, Beijing 102206, China;2. Inner Mongolia Mengniu Dairy (Group) Co. Ltd., Key Laboratory of Dairy Quality Digital Intelligence Monitoring Technology, State Administration for Market Regulation, Hohhot 011517, China)
  • Published:2026-02-04

摘要: 为阐明长双歧杆菌(Bifidobacterium longum)BBMN68菌株酸耐受响应的调控机制,本研究聚焦应答调节蛋白BBMN68_47的功能解析。通过分子克隆技术构建BBMN68_47的3×FLAG标签过表达工程菌株,经聚合酶链式反应扩增、测序及蛋白质免疫印迹验证重组质粒(pDP152-BBMN68_47、pDP152-3×FLAG、pDP152-3×FLAG-BBMN68_47)表达有效性。在pH 4.5弱酸诱导条件下,采用染色质免疫共沉淀测序技术鉴定出118 个高置信度DNA结合峰(>80%位于转录起始位点),结合生物信息学分析预测7 个候选DNA结合基序。进一步通过电泳迁移率变动分析证实BBMN68_47特异性结合两个保守基序:CTGGGCGTTT(探针0235)与CTGGACGAATCCTG(探针0075),分别调控其自身基因(自调控)及metK基因(编码S-腺苷甲硫氨酸合成酶)。结果表明BBMN68_47通过保守/新型DNA基序调控关键耐酸基因网络,在酸耐受响应中发挥核心转录调控作用。该发现为解析双歧杆菌酸适应分子机制及益生菌抗逆性工程改造提供理论依据。

关键词: 长双歧杆菌BBMN68;酸耐受响应;DNA-蛋白质互作;染色质免疫沉淀测序;电泳迁移率变动分析

Abstract: To elucidate the regulatory mechanism of the acid tolerance response (ATR) in Bifidobacterium longum BBMN68, this study investigated the role of response regulator BBMN68_47 in mediating ATR through genomic and proteomic approaches. An overexpression strain of BBMN68_47 with a 3 × FLAG tag was constructed via molecular cloning, and the recombinant plasmids (pDP152-BBMN68_47, pDP152-3 × FLAG, and pDP152-3 × FLAG-BBMN68_47) were validated through polymerase chain reaction (PCR), sequencing, and Western blot. Under weak acid induction (pH 4.5), chromatin immunoprecipitation sequencing (ChIP-seq) identified 118 high-confidence DNA binding peaks, over 80% of which were localized at transcription start sites (TSS). Bioinformatics analysis predicted seven candidate DNA binding motifs. Electrophoretic mobility shift assay (EMSA) analysis further confirmed specific binding of BBMN68_47 to two conserved motifs: CTGGGCGTTT (Probe 0235) and CTGGACGAATCCTG (Probe 0075), regulating the expression of its own gene BBMN68_47 (autoregulatory) and the S-adenosylmethionine synthetase (metK) gene, respectively. These findings establish BBMN68_47 as a central transcriptional regulator in B. longum ATR, orchestrating key acid-resistant gene networks through conserved and novel DNA motifs. This work offers a theoretical basis for elucidating the molecular mechanism of the ATR of B. longum and engineering stress resistance in probiotics.

Key words: Bifidobacterium longum BBMN68; acid tolerance response; DNA-protein interaction; chromatin immunoprecipitation sequencing; electrophoretic mobility shift assay

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