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Title: Classification of a Haemophilus influenzae ABC Transporter HI1470/71 through Its Cognate Molybdate Periplasmic Binding Protein, MolA

molA (HI1472) from H. influenzae encodes a periplasmic binding protein (PBP) that delivers substrate to the ABC transporter MolB{sub 2}C{sub 2} (formerly HI1470/71). The structures of MolA with molybdate and tungstate in the binding pocket were solved to 1.6 and 1.7 {angstrom} resolution, respectively. The MolA-binding protein binds molybdate and tungstate, but not other oxyanions such as sulfate and phosphate, making it the first class III molybdate-binding protein structurally solved. The {approx}100 {mu}M binding affinity for tungstate and molybdate is significantly lower than observed for the class II ModA molybdate-binding proteins that have nanomolar to low micromolar affinity for molybdate. The presence of two molybdate loci in H. influenzae suggests multiple transport systems for one substrate, with molABC constituting a low-affinity molybdate locus.
Authors:
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  1. (CIT)
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Publication Date:
OSTI Identifier:
1034211
Resource Type:
Journal Article
Resource Relation:
Journal Name: Structure; Journal Volume: 19; Journal Issue: (11) ; 11, 2011
Research Org:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Org:
OTHERNIH
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; AFFINITY; CLASSIFICATION; HAEMOPHILUS; MOLYBDATES; PROTEINS; RESOLUTION; SUBSTRATES; SULFATES; TRANSPORT; TUNGSTATES