{"title":"1H, 13C and 15N assignment of self-complemented MrkA protein antigen from Klebsiella pneumoniae","authors":"Valentina Monaci, Gianmarco Gasperini, Lucia Banci, Francesca Micoli, Francesca Cantini","doi":"10.1007/s12104-024-10185-3","DOIUrl":null,"url":null,"abstract":"<div><p>Klebsiella pneumoniae (Kp) poses an escalating threat to public health, particularly given its association with nosocomial infections and its emergence as a leading cause of neonatal sepsis, particularly in low- and middle-income countries (LMICs). Host cell adherence and biofilm formation of Kp is mediated by type 1 and type 3 fimbriae whose major fimbrial subunits are encoded by the <i>fimA</i> and <i>mrkA</i> genes, respectively. In this study, we focus on MrkA subunit, which is a 20 KDa protein whose 3D molecular structure remains elusive. We applied solution NMR to characterize a recombinant version of MrkA in which the donor strand segment situated at the protein’s N-terminus is relocated to the C-terminus, preceded by a hexaglycine linker. This construct yields a self-complemented variant of MrkA. Remarkably, the self-complemented MrkA monomer loses its capacity to interact with other monomers and to extend into fimbriae structures. Here, we report the nearly complete assignment of the <sup>13</sup>C,<sup>15</sup>N labelled self-complemented MrkA monomer. Furthermore, an examination of its internal mobility unveiled that relaxation parameters are predominantly uniform across the polypeptide sequence, except for the glycine-rich region within loop 176–181. These data pave the way to a comprehensive structural elucidation of the MrkA monomer and to structurally map the molecular interaction regions between MrkA and antigen-induced antibodies.</p></div>","PeriodicalId":492,"journal":{"name":"Biomolecular NMR Assignments","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11511707/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biomolecular NMR Assignments","FirstCategoryId":"99","ListUrlMain":"https://link.springer.com/article/10.1007/s12104-024-10185-3","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Klebsiella pneumoniae (Kp) poses an escalating threat to public health, particularly given its association with nosocomial infections and its emergence as a leading cause of neonatal sepsis, particularly in low- and middle-income countries (LMICs). Host cell adherence and biofilm formation of Kp is mediated by type 1 and type 3 fimbriae whose major fimbrial subunits are encoded by the fimA and mrkA genes, respectively. In this study, we focus on MrkA subunit, which is a 20 KDa protein whose 3D molecular structure remains elusive. We applied solution NMR to characterize a recombinant version of MrkA in which the donor strand segment situated at the protein’s N-terminus is relocated to the C-terminus, preceded by a hexaglycine linker. This construct yields a self-complemented variant of MrkA. Remarkably, the self-complemented MrkA monomer loses its capacity to interact with other monomers and to extend into fimbriae structures. Here, we report the nearly complete assignment of the 13C,15N labelled self-complemented MrkA monomer. Furthermore, an examination of its internal mobility unveiled that relaxation parameters are predominantly uniform across the polypeptide sequence, except for the glycine-rich region within loop 176–181. These data pave the way to a comprehensive structural elucidation of the MrkA monomer and to structurally map the molecular interaction regions between MrkA and antigen-induced antibodies.
期刊介绍:
Biomolecular NMR Assignments provides a forum for publishing sequence-specific resonance assignments for proteins and nucleic acids as Assignment Notes. Chemical shifts for NMR-active nuclei in macromolecules contain detailed information on molecular conformation and properties.
Publication of resonance assignments in Biomolecular NMR Assignments ensures that these data are deposited into a public database at BioMagResBank (BMRB; http://www.bmrb.wisc.edu/), where they are available to other researchers. Coverage includes proteins and nucleic acids; Assignment Notes are processed for rapid online publication and are published in biannual online editions in June and December.