WordNet

any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes; "a diet high in protein"

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蛋白(たんばく)質
molybdenumの化学記号

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1. プロテインS欠乏症：臨床症状および診断 protein s deficiency clinical manifestations and diagnosis
2. 幼児の食物蛋白誘発性直腸炎/大腸炎および腸疾患 food protein induced proctitis colitis and enteropathy of infancy
3. プロテインC欠乏症：臨床症状および診断 protein c deficiency clinical manifestations and diagnosis
4. 第V因子ライデンおよび活性化プロテインC抵抗性：臨床症状および診断 factor v leiden and activated protein c resistance clinical manifestations and diagnosis
5. 肥大型心筋症の遺伝学 genetics of hypertrophic cardiomyopathy

English Journal

Substrate Channel in Nitrogenase Revealed by a Molecular Dynamics Approach.

Smith D1, Danyal K, Raugei S, Seefeldt LC.Author information 1Pacific Northwestern National Laboratory , Richland, Washington 99352, United States.AbstractMo-dependent nitrogenase catalyzes the biological reduction of N2 to two NH3 molecules at FeMo-cofactor buried deep inside the MoFe protein. Access of substrates, such as N2, to the active site is likely restricted by the surrounding protein, requiring substrate channels that lead from the surface to the active site. Earlier studies on crystallographic structures of the MoFe protein have suggested three putative substrate channels. Here, we have utilized submicrosecond atomistic molecular dynamics simulations to allow the nitrogenase MoFe protein to explore its conformational space in an aqueous solution at physiological ionic strength, revealing a putative substrate channel. The viability of this observed channel was tested by examining the free energy of passage of N2 from the surface through the channel to FeMo-cofactor, resulting in the discovery of a very low energy barrier. These studies point to a viable substrate channel in nitrogenase that appears during thermal motions of the protein in an aqueous environment and that approaches a face of FeMo-cofactor earlier implicated in substrate binding.
Biochemistry.Biochemistry.2014 Apr 2. [Epub ahead of print]
Mo-dependent nitrogenase catalyzes the biological reduction of N2 to two NH3 molecules at FeMo-cofactor buried deep inside the MoFe protein. Access of substrates, such as N2, to the active site is likely restricted by the surrounding protein, requiring substrate channels that lead from the surface t
PMID 24654842

A confirmation of the quench-cryoannealing relaxation protocol for identifying reduction States of freeze-trapped nitrogenase intermediates.

Lukoyanov D1, Yang ZY, Duval S, Danyal K, Dean DR, Seefeldt LC, Hoffman BM.Author information 1Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322, United States.AbstractWe have advanced a mechanism for nitrogenase catalysis that rests on the identification of a low-spin EPR signal (S = 1/2) trapped during turnover of a MoFe protein as the E4 state, which has accumulated four reducing equivalents as two [Fe-H-Fe] bridging hydrides. Because electrons are delivered to the MoFe protein one at a time, with the rate-limiting step being the off-rate of oxidized Fe protein, it is difficult to directly control, or know, the degree of reduction, n, of a trapped intermediate, denoted En, n = 1-8. To overcome this previously intractable problem, we introduced a quench-cryoannealing relaxation protocol for determining n of an EPR-active trapped En turnover state. The trapped "hydride" state was allowed to relax to the resting E0 state in frozen medium, which prevents additional accumulation of reducing equivalents; binding of reduced Fe protein and release of oxidized protein from the MoFe protein both are abolished in a frozen solid. Relaxation of En was monitored by periodic EPR analysis at cryogenic temperature. The protocol rests on the hypothesis that an intermediate trapped in the frozen solid can relax toward the resting state only by the release of a stable reduction product from FeMo-co. In turnover under Ar, the only product that can be released is H2, which carries two reducing equivalents. This hypothesis implicitly predicts that states that have accumulated an odd number of electrons/protons (n = 1, 3) during turnover under Ar cannot relax to E0: E3 can relax to E1, but E1 cannot relax to E0 in the frozen state. The present experiments confirm this prediction and, thus, the quench-cryoannealing protocol and our assignment of E4, the foundation of the proposed mechanism for nitrogenase catalysis. This study further gives insights into the identity of the En intermediates with high-spin EPR signals, 1b and 1c, trapped under high electron flux.
Inorganic chemistry.Inorg Chem.2014 Apr 7;53(7):3688-93. doi: 10.1021/ic500013c. Epub 2014 Mar 18.
We have advanced a mechanism for nitrogenase catalysis that rests on the identification of a low-spin EPR signal (S = 1/2) trapped during turnover of a MoFe protein as the E4 state, which has accumulated four reducing equivalents as two [Fe-H-Fe] bridging hydrides. Because electrons are delivered to
PMID 24635454

Nonenzymatic synthesis of the P-cluster in the nitrogenase MoFe protein: evidence of the involvement of all-ferrous [Fe4S4](0) intermediates.

Rupnik K1, Lee CC, Wiig JA, Hu Y, Ribbe MW, Hales BJ.Author information 1Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70808, United States.AbstractThe P-cluster in the nitrogenase MoFe protein is a [Fe8S7] cluster and represents the most complex FeS cluster found in Nature. To date, the exact mechanism of the in vivo synthesis of the P-cluster remains unclear. What is known is that the precursor to the P-cluster is a pair of neighboring [Fe4S4]-like clusters found on the ΔnifH MoFe protein, a protein expressed in the absence of the nitrogenase Fe protein (NifH). Moreover, incubation of the ΔnifH MoFe protein with NifH and MgATP results in the synthesis of the MoFe protein P-clusters. To improve our understanding of the mechanism of this reaction, we conducted a magnetic circular dichroism (MCD) spectroscopic study of the [Fe4S4]-like clusters on the ΔnifH MoFe protein. Reducing the ΔnifH MoFe protein with Ti(III) citrate results in the quenching of the S = (1)/2 electron paramagnetic resonance signal associated with the [Fe4S4](+) state of the clusters. MCD spectroscopy reveals this reduction results in all four 4Fe clusters being converted into the unusual, all-ferrous [Fe4S4](0) state. Subsequent increases of the redox potential generate new clusters. Most significantly, one of these newly formed clusters is the P-cluster, which represents approximately 20-25% of the converted Fe concentration. The other two clusters are an X cluster, of unknown structure, and a classic [Fe4S4] cluster, which represents approximately 30-35% of the Fe concentration. Diamagnetic FeS clusters may also have been generated but, because of their low spectral intensity, would not have been identified. These results demonstrate that the nitrogenase P-cluster can be generated in the absence of NifH and MgATP.
Biochemistry.Biochemistry.2014 Feb 25;53(7):1108-16. doi: 10.1021/bi401699u. Epub 2014 Feb 12.
The P-cluster in the nitrogenase MoFe protein is a [Fe8S7] cluster and represents the most complex FeS cluster found in Nature. To date, the exact mechanism of the in vivo synthesis of the P-cluster remains unclear. What is known is that the precursor to the P-cluster is a pair of neighboring [Fe4S4
PMID 24520862

Japanese Journal

Cloning and Characterization of nif Structural and Regulatory Genes in the Purple Sulfur Bacterium, Halorhodospira halophila(GENETICS, MOLECULAR BIOLOGY, AND GENE ENGINEERING)

Tsuihiji Hisayoshi,Yamazaki Yoichi,Kamikubo Hironari [他],Imamoto Yasushi,Kataoka Mikio
Journal of bioscience and bioengineering 101(3), 263-270, 2006-03-25
… The amino-acid sequences of NifH and NifD indicated that these proteins are an Fe protein and a part of a MoFe protein, respectively. …
NAID 110004704904

Cloning and Characterization of nif Structural and Regulatory Genes in the Purple Sulfur Bacterium, Halorhodospira halophila

, , , ,
Journal of Bioscience and Bioengineering 101(3), 263-270, 2006
… The amino-acid sequences of NifH and NifD indicated that these proteins are an Fe protein and a part of a MoFe protein, respectively. …
NAID 130004144593

シグモイド型被覆尿素側条施肥によるダイズの増収効果

高橋能彦,土田徹,大竹憲邦 [他],大山卓爾
日本土壌肥料學雜誌 74(1), 55-60, 2003-02-05
1)ダイズ根粒の窒素固定依存率は最繁期(R3)を頂点とする放物線型をなした。根粒活性の硝酸に対する感受性は最繁期まで明確に認められるが,最繁期以降は植物体としては硝酸吸収による窒素固定の阻害は認められない。したがって,最繁期以降の肥料窒素供給はダイズの窒素固定と調和する。2)ダイズの最繁期以降に溶出が開始される窒素肥料として,施用後一定期間溶出が抑制されるシグモイド型被覆尿素を選定した.溶出タイプ …
NAID 110001746722