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IsdA of Staphylococcus aureus is a broad spectrum, iron‐regulated adhesin
Author(s) -
Clarke Simon R.,
Wiltshire Michael D.,
Foster Simon J.
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2003.03938.x
Subject(s) - bacterial adhesin , staphylococcus aureus , biology , fibronectin , microbiology and biotechnology , bacteria , plasma protein binding , pathogen , ligand (biochemistry) , extracellular matrix , gene , biochemistry , escherichia coli , receptor , genetics
Summary As an important facet of host–pathogen interaction, Staphylococcus aureus has the ability to adhere to human extracellular matrix (ECM) components via a range of surface proteins. Here we have shown that IsdA has broad‐spectrum ligand‐binding activity, including fibrinogen and fibronectin. Mapping studies revealed a distinct domain responsible for ligand binding. This domain is present in a number of iron‐regulated proteins of S. aureus and in other Gram‐positive organisms. The isdA gene is only expressed in iron‐limited conditions under the control of Fur and not in standard laboratory media. Such conditions occur in serum in vitro and during infection. Whole cell binding and clumping assays revealed that when the bacteria are grown under iron‐limited conditions, IsdA constitutes a physiologically relevant adhesin to both fibrinogen and fibronectin. Thus for S. aureus , iron is an important marker for the host environment, to which the bacterium responds by differential regulation of at least one element of its adhesive strategy.