Fusion of a bacterial cadherin-like domain and green fluorescent protein as a specific probe to study biofilm matrix formation in Rhizobium spp

MALORI, MARÍA SOLEDAD; RUSSO, DANIELA M.; BENINTENDE, GRACIELA; ABDIAN, PATRICIA L. (CORRESPONDING AUTHOR); CHECCHI, ABI MAGLIO; BERRETTA, MARCELO F.; CARAMELO, JULIO J.; ZORREGUIETA, ANGELES

MICROBIOLOGY-UK

SOC GENERAL MICROBIOLOGY

Año: 2022 vol. 168

1350-0872

Rhizobium adhering proteins or ?Raps? are secreted proteins identified in a very restricted group of rhizobial strains, specificallythose belonging to R. leguminosarum and R. etli. The distinctive feature of members of the Rap family is the presence of one ortwo cadherin-likedomains or CHDLs that are also present in numerous extracellular bacterial and archaeal proteins and wereproposed to confer carbohydrate binding ability. We have previously made an in-depthcharacterization of RapA2, a calcium-bindinglectin, composed by two CHDLs, involved in biofilm matrix remodelling in R. leguminosarum bv. viciae 3841. In thisstudy, CHDLs derived from RapA2 were analysed in detail, finding significant structural and functional differences despite theirconsiderable sequence similarity. Only the carboxy-terminalCHDL retained properties similar to those displayed by RapA2. Ourfindings were used to obtain a novel fluorescent probe to study biofilm matrix development by confocal laser scanning microscopy,and also to shed some light on the role of the ubiquitous CHDL domains in bacterial secreted proteins.