• 제목/요약/키워드: Structural biology

검색결과 837건 처리시간 0.035초

Mobilization of Photosystem II-Light Harvesting Complex II Supercomplexes during High Light Illumination and State Transitions

  • Nath, Krishna;Elizabeth, John;Poudyal, Roshan Sharma;Ko, Su Yeon;Lim, Woon Ki;Lee, Choon-Hwan
    • Rapid Communication in Photoscience
    • /
    • 제2권1호
    • /
    • pp.18-23
    • /
    • 2013
  • The photosystem II (PSII) light harvesting complex (LHC) consists of a variety of pigment protein complexes which are involved in structural organization and regulation of photosynthetic unit. These LHC proteins encoded by a group of Lhcb genes are essential for the structural integrity of PSII supercomplex, the channeling the excitation energy to the reaction center of PSII and its redistribution to photosystem I by state transitions. Numerous studies with the help of recent technological advancements have enabled a significant progress in our understanding on the structure of PSII-LHCII supercomplexes and their mobilization under various light conditions. Here, we present a mini-review on the latest concepts and models depicting the structure of PSII-LHCII supercomplexes and the role of Lhcb proteins in their supra-molecular organization. Also we will review on the current understandings and remaining problems involved in the mobilization of the supercomplexes during state transitions and during high light illumination for controlling light energy distribution between the two photosystems.

Unfolded Histidine-Tagged Protein is Immobilized to Nitrilotriacetic Acid-Nickel Beads, But Not the Nickel-Coated Glass Slide

  • Cho Min-Ho;Ahn Sun-Young;Park Heon-Yong
    • Genomics & Informatics
    • /
    • 제4권3호
    • /
    • pp.133-136
    • /
    • 2006
  • The adsorption of proteins on the surface of glass slides is essential for construction of protein chips. Previously, we prepared a nickel-coated plate by the spin-coating method for immobilization of His-tagged proteins. In order to know whether the structural factor is responsible for the immobilization of His-tagged proteins to the nickel-coated glass slide, we executed a series of experiments. First we purified a His-tagged protein after expressing the vector in E. coli BL21 (DE3). Then we obtained the unfolding curve for the His-tagged protein by using guanidine hydrochloride. Fractions unfolded were monitored by internal fluorescence spectroscopy. The ${\Delta}G_{H20}$ for unfolding was $2.27kcal/mol{/pm}0.52$. Then we tested if unfolded His-tagged proteins can be adsorbed to the nickel-coated plate, comparing with $Ni^{2+}-NTA$ (nitrilotriacetic acid) beads. Whereas unfolded His-tagged proteins were adsorbed to $Ni^{2+}-NTA$ beads, they did not bind to the nickel-coated plate. In conclusion, a structural factor is likely to be an important factor for constructing the protein chips, when His-tagged proteins will immobilize to the nickel-coated slides.

Karyological Variation of Callus-derived Regenerants in Allium victorialis var. platyphyllum

  • Seo, Bong-Bo;Lee, Seon-Hee;Park, Jae-Hong;Kim, In-Sun;Song, Seung-Dal
    • Journal of Plant Biology
    • /
    • 제39권4호
    • /
    • pp.231-235
    • /
    • 1996
  • The calli obtained from the bulbs of A. victorialis var. platyphyllum on MS based medium containing 2 mg/L 2, 4-D and 1mg/L BA. Plants from calli were regenerated on MS basal media supplemented with combinations of NAA and four kinds of cytokinin, BA, zeatin, kinetin and 2iP, and with only each cytokinin. The good response of shoot regeneration was observed in the media with combinations of NAA and BA or zeatin, and with only BA or zeatin. Shoot regenerating response in the medium with combinations of NAA and BA or zeatin, and with only BA or zeatin. Shoot regerating response in the medium with combinations of NAA and BA or zeatin was about two times higher than that in the mediuim with only BA or zeatin. From the karyotypic analysis of the regenerated plants, abnormal diploids, aneuploids and mixoploid with structural aberrations were investigated. The somaclonal variants (AV 16-04, AV 13-03) were shown the considerable differences from normal diploid regenerant (AV 18-03) in the external morphology.

  • PDF

Protein Backbone Torsion Angle-Based Structure Comparison and Secondary Structure Database Web Server

  • Jung, Sunghoon;Bae, Se-Eun;Ahn, Insung;Son, Hyeon S.
    • Genomics & Informatics
    • /
    • 제11권3호
    • /
    • pp.155-160
    • /
    • 2013
  • Structural information has been a major concern for biological and pharmaceutical studies for its intimate relationship to the function of a protein. Three-dimensional representation of the positions of protein atoms is utilized among many structural information repositories that have been published. The reliability of the torsional system, which represents the native processes of structural change in the structural analysis, was partially proven with previous structural alignment studies. Here, a web server providing structural information and analysis based on the backbone torsional representation of a protein structure is newly introduced. The web server offers functions of secondary structure database search, secondary structure calculation, and pair-wise protein structure comparison, based on a backbone torsion angle representation system. Application of the implementation in pair-wise structural alignment showed highly accurate results. The information derived from this web server might be further utilized in the field of ab initio protein structure modeling or protein homology-related analyses.

The Solution Structure of FADD Death Domain: Structural Basis of Death Domain Interactions of Fas and FADD

  • Jeong, Euj-Jun;SookHee, Bang;Kim, Key-Sun
    • 한국생물물리학회:학술대회논문집
    • /
    • 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
    • /
    • pp.21-21
    • /
    • 1999
  • A signal of Fas-mediated apoptosis is transferred through an adaptor protein FADD by interactions between death domains of Fas and FADD. To understand the signal transduction mechanism of Fas-mediated apoptosis, we solved the solution structure of a murine FADD death domain.(omitted)

  • PDF

Bacillus thuringiensis Cry4A and Cry4B Mosquito-larvicidal Proteins: Homology-based 3D Model and Implications for Toxin Activity

  • Angsuthanasombat, Chanan;Uawithya, Panapat;Leetachewa, Somphob;Pornwiroon, Walairat;Ounjai, Puey;Kerdcharoen, Teerakiat;Katzenmeier, Gerd;Panyim, Sakol
    • BMB Reports
    • /
    • 제37권3호
    • /
    • pp.304-313
    • /
    • 2004
  • Three-dimensional (3D) models for the 65-kDa activated Cry4A and Cry4B $\delta$-endotoxins from Bacillus thuringiensis subsp. israelensis that are specifically toxic to mosquito-larvae were constructed by homology modeling, based on atomic coordinates of the Cry1Aa and Cry3Aa crystal structures. They were structurally similar to the known structures, both derived 3D models displayed a three-domain organization: the N-terminal domain (I) is a seven-helix bundle, while the middle and C-terminal domains are primarily comprise of anti-parallel $\beta$-sheets. Circular dichroism spectroscopy confirmed the secondary structural contents of the two homology-based Cry4 structures. A structural analysis of both Cry4 models revealed the following: (a) Residues Arg-235 and Arg-203 are located in the interhelical 5/6 loop within the domain I of Cry4A and Cry4B, respectively. Both are solvent exposed. This suggests that they are susceptible to tryptic cleavage. (b) The unique disulphide bond, together with a proline-rich region within the long loop connecting ${\alpha}4$ and ${\alpha}5$ of Cry4A, were identified. This implies their functional significance for membrane insertion. (c) Significant structural differences between both models were found within domain II that may reflect their different activity spectra. Structural insights from this molecular modeling study would therefore increase our understanding of the mechanic aspects of these two closely related mosquito-larvicidal proteins.

Structural flexibility of Escherichia coli IscU, the iron-sulfur cluster scaffold protein

  • Kim, Bokyung;Kim, Jin Hae
    • 한국자기공명학회논문지
    • /
    • 제24권3호
    • /
    • pp.86-90
    • /
    • 2020
  • Iron-sulfur (Fe-S) clusters are one of the most ancient yet essential cofactors mediating various essential biological processes. In prokaryotes, Fe-S clusters are generated via several distinctive biogenesis mechanisms, among which the ISC (Iron-Sulfur Cluster) mechanism plays a house-keeping role to satisfy cellular needs for Fe-S clusters. The Escherichia coli ISC mechanism is maintained by several essential protein factors, whose structural characterization has been of great interest to reveal mechanistic details of the Fe-S cluster biogenesis mechanisms. In particular, nuclear magnetic resonance (NMR) spectroscopic approaches have contributed much to elucidate dynamic features not only in the structural states of the protein components but also in the interaction between them. The present minireview discusses recent advances in elucidating structural features of IscU, the key player in the E. coli ISC mechanism. IscU accommodates exceptional structural flexibility for its versatile activities, for which NMR spectroscopy was particularly successful. We expect that understanding to the structural diversity of IscU provides critical insight to appreciate functional versatility of the Fe-S cluster biogenesis mechanism.