biostudies-literatureUnknown64(Pt 6)Kaushal PSThe crystal structure of high-salt horse methaemoglobin has been determined at environmental relative humidities (r.h.) of 88, 79, 75 and 66%. The molecule is in the R state in the native and the r.h. 88% crystals. At r.h. 79%, the water content of the crystal is reduced and the molecule appears to move towards the R2 state. The crystals undergo a water-mediated transformation involving a doubling of one of the unit-cell parameters and an increase in water content when the environmental humidity is further reduced to r.h. 75%. The water content is now similar to that in the native crystals and the molecules are in the R state. The crystal structure at r.h. 66% is similar, but not identical, to that at r.h. 75%, but the solvent content is substantially reduced and the molecules have a quateActa crystallographica. Section F, Structural biology and crystallization communications463-9https://www.ebi.ac.uk/biostudies/studies/S-EPMC2496843biostudies-literatureWater-mediated variability in the structure of relaxed-state haemoglobin.PMC2496843Vijayan MSankaranarayanan RKaushal PSfalseWater-mediated variability in the structure of relaxed-state haemoglobin.The crystal structure of high-salt horse methaemoglobin has been determined at environmental relative humidities (r.h.) of 88, 79, 75 and 66%. The molecule is in the R state in the native and the r.h. 88% crystals. At r.h. 79%, the water content of the crystal is reduced and the molecule appears to move towards the R2 state. The crystals undergo a water-mediated transformation involving a doubling of one of the unit-cell parameters and an increase in water content when the environmental humidity is further reduced to r.h. 75%. The water content is now similar to that in the native crystals and the molecules are in the R state. The crystal structure at r.h. 66% is similar, but not identical, to that at r.h. 75%, but the solvent content is substantially reduced and the molecules have a quate2008-01-01T00:00:00Z2008 Jun2025-06-01T11:59:32.488Z2019-03-27T00:13:57ZS-EPMC24968431854005210.1107/S174430910801310910.1107/s1744309108013109