1z3y is a 1 chain structure with sequence from Thermosynechococcus elongatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Gun4 has been implicated in a developmental signaling pathway between the chloroplast and the nucleus involving magnesium protoporphyrin IX (MgP(IX)), the first dedicated intermediate in the chlorophyll biosynthetic pathway. Here we present the crystal structure of Thermosynechococcus elongatus Gun4 at 1.5 A, describe the binding affinities of Gun4 for substrate and product porphyrin molecules, and identify a likely (Mg)P(IX) binding site on the protein. Kinetic analyses show that Gun4 dramatically increases the efficiency of transformation of porphyrin substrate to metalloporphyrin product and that it also reduces the threshold Mg2+ concentration required for activity at low porphyrin concentration. Gun4 therefore controls magnesium chelatase at physiologically significant Mg2+ concentrations and likely acts as a molecular switch in vivo so that in its absence magnesium chelatase is inactive. This mechanism could allow Gun4 to mediate magnesium protoporphyrin levels both for chlorophyll biosynthesis and for signaling to the nucleus.
Structural and biochemical characterization of Gun4 suggests a mechanism for its role in chlorophyll biosynthesis.,Davison PA, Schubert HL, Reid JD, Iorg CD, Heroux A, Hill CP, Hunter CN Biochemistry. 2005 May 31;44(21):7603-12. PMID:15909975[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Davison PA, Schubert HL, Reid JD, Iorg CD, Heroux A, Hill CP, Hunter CN. Structural and biochemical characterization of Gun4 suggests a mechanism for its role in chlorophyll biosynthesis. Biochemistry. 2005 May 31;44(21):7603-12. PMID:15909975 doi:http://dx.doi.org/10.1021/bi050240x
