Functional aspects of the heme bound hemophore HasA by structural analysis of various crystal forms

Arnoux, Pascal; Haser, R.; Izadi-Pruneyre, Nadia; Lecroisey, Anne; Czjzek, Mirjam

doi:10.1002/1097-0134(20001101)41:2<202::aid-prot50>3.0.co;2-8

Cited by 45 publications

(46 citation statements)

References 35 publications

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“…Two types of hemophore-mediated heme uptake systems have been described for Gram-negative bacteria: one uses the HasA hemophore, and the other uses the HxuA hemophore (116). The HasA hemophore-mediated heme uptake system has been identified in Serratia marcescens, P. aeruginosa, Pseudomonas fluorescens, and Y. pestis (4,45,56,58,96). The HasA system encodes an export complex (HasDEF), a hemophore receptor (HasR), and regulatory proteins (HasI and HasS) (7,15,33,97,116).…”

Section: Heme Sources Exploited By Bacterial Pathogenssupporting

confidence: 77%

Overcoming the Heme Paradox: Heme Toxicity and Tolerance in Bacterial Pathogens

2010

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Virtually all bacterial pathogens require iron to infect vertebrates. The most abundant source of iron within vertebrates is in the form of heme as a cofactor of hemoproteins. Many bacterial pathogens have elegant systems dedicated to the acquisition of heme from host hemoproteins. Once internalized, heme is either degraded to release free iron or used intact as a cofactor in catalases, cytochromes, and other bacterial hemoproteins. Paradoxically, the high redox potential of heme makes it a liability, as heme is toxic at high concentrations. Although a variety of mechanisms have been proposed to explain heme toxicity, the mechanisms by which heme kills bacteria are not well understood. Nonetheless, bacteria employ various strategies to protect against and eliminate heme toxicity. Factors involved in heme acquisition and detoxification have been found to contribute to virulence, underscoring the physiological relevance of heme stress during pathogenesis. Herein we describe the current understanding of the mechanisms of heme toxicity and how bacterial pathogens overcome the heme paradox during infection.

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Section: Heme Sources Exploited By Bacterial Pathogenssupporting

confidence: 77%

Overcoming the Heme Paradox: Heme Toxicity and Tolerance in Bacterial Pathogens

2010

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“…The 1300 -1700 cm Ϫ1 region of heme rR spectra comprises bands corresponding to porphyrin in-plane vibrational modes. They are diagnostic for oxidation (19,26). The low resolution of the electron density might be due to high flexibility and/or the presence of several conformations.…”

Section: Resonance Raman Spectra Of Holohasa Wt and Holoh83a Mutantmentioning

confidence: 94%

“…2). Therefore, the geometry of the heme group was tightly constrained to standard values and refined in the two heme orientations related by 180°rotation along the ␣-␥ meso axis identified in holoHasA WT (19,26). Water molecules were added with CCP4/wARP (27).…”

Section: Methodsmentioning

confidence: 99%

Deciphering the Structural Role of Histidine 83 for Heme Binding in Hemophore HasA

Caillet‐Saguy

Turano

Piccioli

et al. 2008

Journal of Biological Chemistry

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“…Structures of the wild type heme-loaded HasA (holo-HasA WT ) ( Fig. 1) (7,8) and heme-free HasA (apoHasA WT ) (9) are available. The protein presents an original ␣/␤ fold with a highly curved seven-stranded antiparallel ␤-sheet on one face and a bundle of four ␣-helices on the other face.…”

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confidence: 99%