Consequences of Counterion Mutation in Sensory Rhodopsin II of<i>Natronobacterium pharaonis</i>for Photoreaction and Receptor Activation: An FTIR Study

Hein, Michael; Radu, Ionela; Klare, Johann P.; Engelhard, Martin; Siebert, Friedrich

doi:10.1021/bi0354381

Cited by 17 publications

(22 citation statements)

References 46 publications

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“…In both instances the proteins are capable for transition to the signaling state. Infrared spectroscopic data indicated that the conformational changes observed upon activation of the NpSRII-D75N mutant are almost identical to those observed for the wild type [15]. It is in line with the observation that this mutant displays wild type physiological behavior and gives additional confidence for the structural explanation of the unexpected consequence of D75N mutation described above.…”

Section: Discussionsupporting

confidence: 84%

“…showed that photocycle related conformational changes in wild type and D75N mutant are quite similar indicating that the neutralization of the Schiff base counter ion does not interfere with the formation of the active state [15]. Here we present the crystal structure of the ground state of the mutant NpSRII-D75N/NpHtrII complex in the space group I212121 that provides us with additional information about signal transduction.…”

Section: Introductionmentioning

confidence: 91%

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Ground state structure of D75N mutant of sensory rhodopsin II in complex with its cognate transducer

Ishchenko

Borshchevskiy

Grudinin

et al. 2013

Journal of Photochemistry and Photobiology B: Biology

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International audienceThe complex of sensory rhodopsin II (NpSRII) with its cognate transducer (NpHtrII) mediates negative phototaxis in halobacteria Natronomonas pharaonis. Upon light activation NpSRII triggers, by means of NpHtrII, a signal transduction chain homologous to the two component system in eubacterial chemotaxis. Here we report on the crystal structure of the ground state of the mutant NpSRII-D75N/NpHtrII complex in the space group I212121. Mutations of this aspartic acid in light-driven proton pumps dramatically modify or/and inhibit protein functions. However, in vivo studies show that the similar D75N mutation retains functionality of the NpSRII/NpHtrII complex. The structure provides the molecular basis for the explanation of the unexpected observation that the wild and the mutant complexes display identical physiological response on light excitation

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 91%

Ground state structure of D75N mutant of sensory rhodopsin II in complex with its cognate transducer

Ishchenko

Borshchevskiy

Grudinin

et al. 2013

Journal of Photochemistry and Photobiology B: Biology

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“…As expected from this function, photocycling of the Asp mutants in HsSRII and NpSRII exhibited no M formation (data not shown). Instead, the mutants of HsSRII accumulated a slightly blue‐shifted intermediate with depleted absorption near 500 nm relative to the initial state (Spudich et al ., 1997), whereas those of NpSRII accumulated an intermediate with a red‐shifted absorption compared with the initial state, as previously reported for D75N (Schmies et al ., 2000; Sudo et al ., 2002; Hein et al ., 2004; Inoue et al ., 2007).…”

Section: Resultsmentioning

confidence: 99%

Constitutive activity in chimeras and deletions localize sensory rhodopsin II/HtrII signal relay to the membrane‐inserted domain

Sasaki

Nara

Spudich

et al. 2007

Molecular Microbiology

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SummaryHalobacterium salinarum sensory rhodopsin II (HsSRII) is a phototaxis receptor for blue-light avoidance that relays signals to its tightly bound transducer HsHtrII (H. salinarum haloarchaeal transducer for SRII). We found that disruption of the salt bridge between the protonated Schiff base of the receptor's retinylidene chromophore and its counterion Asp73 by residue substitutions D73A, N or Q constitutively activates HsSRII, whereas the corresponding Asp75 counterion substitutions do not constitutively activate Natronomonas pharaonis SRII (NpSRII) when complexed with N. pharaonis haloarchaeal transducer for SRII (NpHtrII). However, NpSRII D75Q in complex with HsHtrII is fully constitutively active, showing that transducer sensitivity to the receptor signal contributes to the phenotype. The swimming behaviour of cells expressing chimeras exchanging portions of the two homologous transducers localizes their differing sensitivities to the HtrII transmembrane domains. Furthermore, deletion constructs show that the known contact region in the cytoplasmic domain of the NpSRII-NpHtrII complex is not required for phototaxis, excluding the domain as a site for signal transmission. These results distinguish between the prevailing models for SRII-HtrII signal relay, strongly supporting the 'steric triggertransmembrane relay model', which proposes that retinal isomerization directly signals HtrII through the mid-membrane SRII-HtrII interface, and refuting alternative models that propose signal relay in the cytoplasmic membrane-proximal domain.

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“…The spectrum of the D75N SRII-HtrII complex (Fig. 3, top trace) recorded within the first 50 ms shows predominant formation of the red-shifted O-like state instead of M as indicated by a strong positive band at 1192 cm Ϫ1 (36). Despite the photocycle differences, a comparison of the D75N and D75N/Y199F samples (Fig.…”

Section: Spectral Changes In the Srii-htrii Complex Due Tomentioning

confidence: 96%

“…This peak is superimposed on a pair of intense positive/negative bands at 1700/1685 cm Ϫ1 assigned to Asn 75 in the D75N mutant receptor (36). (Fig.…”

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confidence: 96%

Photoactivation Perturbs the Membrane-embedded Contacts between Sensory Rhodopsin II and Its Transducer

Bergo

Spudich

Rothschild

et al. 2005

Journal of Biological Chemistry

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The photoactivation mechanism of the sensory rhodopsin II (SRII)-HtrII receptor-transducer complex of Natronomonas pharaonis was investigated by time-resolved Fourier transform infrared difference spectroscopy to identify structural changes associated with early events in the signal relay mechanism from the receptor to the transducer. Several prominent bands in the wild-type SRII-HtrII spectra are affected by amino acid substitutions at the receptor Sensory rhodopsin II (SRII)1 functions as a phototaxis receptor for blue light avoidance in several halophilic archaea (1-4). This protein belongs to a growing family of microbial rhodopsins, seven-helix retinylidene membrane proteins now found in all domains of life (5-8). The SRII receptor forms a tight intermolecular complex with its cognate transducer protein HtrII in the cell membrane. The transducer, like its homologous methyl-accepting chemotaxis transducers, possesses two transmembrane helices and a large cytoplasmic domain that binds at its distal end a His-kinase that phosphorylates a flagellar motor switch regulator (1, 9).Interactions of HtrII with the SRII receptor are localized to the transducer transmembrane and membrane-proximal domains (10, 11). A crystal structure of SRII bound to an Nterminal HtrII fragment containing the transmembrane helices (TM1 and TM2) shows tight van der Waals interaction and three hydrogen bonds between TM2 and SRII helices F and G (12). An atomic structure of the membrane-proximal domain of the transducer is not available; however, fluorescent probe accessibility and Förster resonance energy transfer measurements show interaction of this domain with the cytoplasmic E-F loop of the receptor (13).The signal relay mechanism from SRII to HtrII in the complex has become a focus of interest in the past several years, in part because of its importance to the general understanding of interaction between integral membrane proteins. In accord with the unified model for transport and signaling by microbial rhodopsins (14, 15), the key event in the transducer activation is an outward tilt of the receptor helix F during the lifetime of its M intermediate, which has been directly detected by EPR of paramagnetic probes in the free receptor (16) and in its complex with transducer (17). In a response to the helix F movements, the TM2 of HtrII is displaced from its initial position (17). Additional structural changes were observed in the cytoplasmic membrane proximal region by fluorescent probe accessibility measurements (13).Fourier transform infrared (FTIR) difference spectroscopy has been used extensively in the past to elucidate structural changes in the photocycles of several microbial rhodopsins (18 -27). This technique measures changes in the infrared absorption of protein groups and enables studies of light-induced conformational changes without the necessity of introducing potentially structure-perturbing probes. Because of its sensitivity to small changes in hydrogen bonding, it is especially well suited for the study of interacti...

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Consequences of Counterion Mutation in Sensory Rhodopsin II ofNatronobacterium pharaonisfor Photoreaction and Receptor Activation: An FTIR Study

Cited by 17 publications

References 46 publications

Ground state structure of D75N mutant of sensory rhodopsin II in complex with its cognate transducer

Ground state structure of D75N mutant of sensory rhodopsin II in complex with its cognate transducer

Constitutive activity in chimeras and deletions localize sensory rhodopsin II/HtrII signal relay to the membrane‐inserted domain

Photoactivation Perturbs the Membrane-embedded Contacts between Sensory Rhodopsin II and Its Transducer

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