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HU‐α binds to the putative double‐stranded DNA mimic HI1450 from Haemophilus influenzae
Author(s) -
Parsons Lisa M.,
Liu Fang,
Orban John
Publication year - 2005
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.041275705
Subject(s) - haemophilus influenzae , dna , uracil dna glycosylase , binding site , biophysics , uracil , hmg box , nuclear magnetic resonance spectroscopy , chemistry , protein structure , biology , stereochemistry , biochemistry , crystallography , dna binding protein , dna glycosylase , dna repair , gene , transcription factor , antibiotics
Recently, the solution structure of the hypothetical protein HI1450 from Haemophilus influenzae was solved as part of a structure‐based effort to understand function. The distribution of its many negatively charged residues and weak structure and sequence homology to uracil DNA glycosylase inhibitor (Ugi) suggested that HI1450 may act as a double‐stranded DNA (dsDNA) mimic. We present supporting evidence here and show that HI1450 interacts with the dsDNA‐binding protein HU‐α. The interaction between HI1450 and HU‐α from H. influenzae is characterized using calorimetry and NMR spectroscopy. HU‐α binds to HI1450 with a K d of 3.0 ± 0.2 μM, which is similar in affinity to its interaction with dsDNA. Chemical shift perturbation data indicate that the β1‐strand of HI1450 and neighboring regions are most directly involved in interactions with HU‐α. These results show that HI1450 and its structural homolog, Ugi, use similar parts of their structures to recognize DNA‐binding proteins.