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High-resolution crystal structures of the flavoprotein NrdI in oxidized and reduced states - an unusual flavodoxin: Structural biology.

Johansson, Renzo LU ; Torrents, Eduard; Lundin, Daniel; Sprenger, Janina LU ; Sahlin, Margareta; Sjöberg, Britt-Marie and Logan, Derek LU (2010) In The FEBS Journal 277(20). p.4265-4277
Abstract
The small flavoprotein NrdI is an essential component of the class Ib ribonucleotide reductase system in many bacteria. NrdI interacts with the class Ib radical generating protein NrdF. It is suggested to be involved in the rescue of inactivated diferric centres or generation of active dimanganese centres in NrdF. Although NrdI bears a superficial resemblance to flavodoxin, its redox properties have been demonstrated to be strikingly different. In particular, NrdI is capable of two-electron reduction, whereas flavodoxins are exclusively one-electron reductants. This has been suggested to depend on a lesser destabilization of the negatively-charged hydroquinone state than in flavodoxins. We have determined the crystal structures of NrdI... (More)
The small flavoprotein NrdI is an essential component of the class Ib ribonucleotide reductase system in many bacteria. NrdI interacts with the class Ib radical generating protein NrdF. It is suggested to be involved in the rescue of inactivated diferric centres or generation of active dimanganese centres in NrdF. Although NrdI bears a superficial resemblance to flavodoxin, its redox properties have been demonstrated to be strikingly different. In particular, NrdI is capable of two-electron reduction, whereas flavodoxins are exclusively one-electron reductants. This has been suggested to depend on a lesser destabilization of the negatively-charged hydroquinone state than in flavodoxins. We have determined the crystal structures of NrdI from Bacillus anthracis, the causative agent of anthrax, in the oxidized and semiquinone forms, at resolutions of 0.96 and 1.4 Å, respectively. These structures, coupled with analysis of all curated NrdI sequences, suggest that NrdI defines a new structural family within the flavodoxin superfamily. The conformational behaviour of NrdI in response to FMN reduction is very similar to that of flavodoxins, involving a peptide flip in a loop near the N5 atom of the flavin ring. However, NrdI is much less negatively charged than flavodoxins, which is expected to affect its redox properties significantly. Indeed, sequence analysis shows a remarkable spread in the predicted isoelectric points of NrdIs, from approximately pH 4-10. The implications of these observations for class Ib ribonucleotide reductase function are discussed. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ribonucleotide reductase, crystal structure, flavodoxin, NrdI, flavin mononucleotide
in
The FEBS Journal
volume
277
issue
20
pages
4265 - 4277
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • wos:000282326600014
  • pmid:20831589
  • scopus:77957270576
ISSN
1742-464X
DOI
10.1111/j.1742-4658.2010.07815.x
language
English
LU publication?
yes
id
be4766ca-62d2-4813-827e-36b4ab8c0fde (old id 1688305)
date added to LUP
2010-10-18 10:22:55
date last changed
2018-05-29 12:28:08
@article{be4766ca-62d2-4813-827e-36b4ab8c0fde,
  abstract     = {The small flavoprotein NrdI is an essential component of the class Ib ribonucleotide reductase system in many bacteria. NrdI interacts with the class Ib radical generating protein NrdF. It is suggested to be involved in the rescue of inactivated diferric centres or generation of active dimanganese centres in NrdF. Although NrdI bears a superficial resemblance to flavodoxin, its redox properties have been demonstrated to be strikingly different. In particular, NrdI is capable of two-electron reduction, whereas flavodoxins are exclusively one-electron reductants. This has been suggested to depend on a lesser destabilization of the negatively-charged hydroquinone state than in flavodoxins. We have determined the crystal structures of NrdI from Bacillus anthracis, the causative agent of anthrax, in the oxidized and semiquinone forms, at resolutions of 0.96 and 1.4 Å, respectively. These structures, coupled with analysis of all curated NrdI sequences, suggest that NrdI defines a new structural family within the flavodoxin superfamily. The conformational behaviour of NrdI in response to FMN reduction is very similar to that of flavodoxins, involving a peptide flip in a loop near the N5 atom of the flavin ring. However, NrdI is much less negatively charged than flavodoxins, which is expected to affect its redox properties significantly. Indeed, sequence analysis shows a remarkable spread in the predicted isoelectric points of NrdIs, from approximately pH 4-10. The implications of these observations for class Ib ribonucleotide reductase function are discussed.},
  author       = {Johansson, Renzo and Torrents, Eduard and Lundin, Daniel and Sprenger, Janina and Sahlin, Margareta and Sjöberg, Britt-Marie and Logan, Derek},
  issn         = {1742-464X},
  keyword      = {ribonucleotide reductase,crystal structure,flavodoxin,NrdI,flavin mononucleotide},
  language     = {eng},
  number       = {20},
  pages        = {4265--4277},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {The FEBS Journal},
  title        = {High-resolution crystal structures of the flavoprotein NrdI in oxidized and reduced states - an unusual flavodoxin: Structural biology.},
  url          = {http://dx.doi.org/10.1111/j.1742-4658.2010.07815.x},
  volume       = {277},
  year         = {2010},
}