TYROSTATIN IS A NATURAL INHIBITOR, COMPOSED OF ISOVALERYL-TYROSYL-LEUSYL-TYROSINAL. IN 1GA1 AND ...TYROSTATIN IS A NATURAL INHIBITOR, COMPOSED OF ISOVALERYL-TYROSYL-LEUSYL-TYROSINAL. IN 1GA1 AND 1GA4, THE PROTEIN WAS CRYSTALLIZED WITH THE VARIANT OF THIS INHIBITOR, WHERE THE SECOND TYR HAD IODINE INSTEAD OF HYDROXYL, SO IN FACT IT IS P-IODOPHENYLALANINE. IN 1GA6, TYR WAS USED. WHAT THE AUTHORS OBSERVED IN 1GA4, WAS THE TRIPEPTIDE NOT TETRAPEPTIDE, LACKING THE LEU RESIDUE BETWEEN TWO AROMATIC RESIDUES. THIS IS CERTAIN, BUT IT IS NOT CLEAR HOW SUCH A MODIFIED ENTITY ENDED UP IN THE STRUCTURE, AS DISCUSSED IN THE PRIMARY REFERENCE. IN 1GA1 AND 1GA6 ONLY PARTS OF THE INHIBITOR (PARTIALLY OCCUPIED AS WELL) ARE VISIBLE IN THE ELECTRON DENSITY AND ARE MODELED AS A TYROSINE IN 1GA6 AND IODOPHENYLALANINE IN 1GA1 ACCOMPANIED BY JUST MAIN CHAIN PARTS OF ADJOINING RESIDUES, THEREFORE REPRESENTED AS UNK, UNKNOWNS. IN 1GA6 THERE WAS NO DENSITY FOR THE RESIDUE EXPECTED TO BIND TO THE N-TERMINUS OF THE AROMATIC. THE IDENTIFICATION OF IODINE IN 1GA1 WAS CONFIRMED UNEQUIVOCALLY BY ITS ANOMALOUS SCATTERING SIGNAL IN THE ANOMALOUS FOURIER MAP. THEREFORE IN 1GA4 THE AUTHORS CALLED THE MODIFIED INHIBITOR, LACKING LEU IN THE MIDDLE, AS "PSEUDOIODOTYROSTATIN". IN TWO OTHER STRUCTURES THE AUTHORS ARE NOT SURE WHAT IS REALLY THERE, SO THE INHIBITOR IS DESCRIBED AS "FRAGMENTS OF IODOTYROSTATIN" IN 1GA1 AND "FRAGMENTS OF TYROSTATIN" IN 1GA6.
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実験情報
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実験
実験
手法: X線回折 / 使用した結晶の数: 1
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試料調製
結晶
マシュー密度: 2.94 Å3/Da / 溶媒含有率: 58.16 %
結晶化
温度: 293 K / 手法: 蒸気拡散法, ハンギングドロップ法 / pH: 3.5 詳細: 5% guanidine, 7% glycerol, 5% methanol, 1 M ammoniumm sulfate, 0.1 M sodium citrate buffer pH 3.5, VAPOR DIFFUSION, HANGING DROP, temperature 293K