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The positions of eight Se atoms in a selenomethionyl 35 kDa protein were determined at 2.0 and 2.5 Å resolution using the direct-methods program SnB. Data at the selenium peak, edge and remote wavelengths were measured and processed independently. Anomalous difference E magnitudes at each wavelength were derived by two different procedures: renormalized diffE values were calculated according to the equation diffE = {
[(f + 
+ 
]
|
| − |
|}
, where q is a least-squares fitted renormalization function of sinθ/λ such that 〈diffE2〉 = 1.0; and difference E magnitudes were calculated from 
. Locally normalized E magnitudes corresponding to |FA| were also derived from the combination of the data at all three wavelengths through the use of the MADSYS program suite. Each of the independent sets of anomalous difference E magnitudes was capable of producing the correct solution, as did the E data obtained from the FA data. Higher success rates with SnB were observed for the 2.0 Å peak and edge diffE data.
[(f + 
+ 
]
|
| − |
|}
, where q is a least-squares fitted renormalization function of sinθ/λ such that 〈diffE2〉 = 1.0; and difference E magnitudes were calculated from 
. Locally normalized E magnitudes corresponding to |FA| were also derived from the combination of the data at all three wavelengths through the use of the MADSYS program suite. Each of the independent sets of anomalous difference E magnitudes was capable of producing the correct solution, as did the E data obtained from the FA data. Higher success rates with SnB were observed for the 2.0 Å peak and edge diffE data.
