Dear All, I am trying to run " LigandFit " with the following hydrated magnesium hexahydrate cluster (without the hydrogens) pdb. "HETATM 7 MG MG6 A 1 -53.936 117.342 91.273 1.00128.70 A MG HETATM 2 O1 MG6 A 1 -55.351 117.224 89.749 1.00128.62 A O HETATM 3 O2 MG6 A 1 -52.532 117.421 92.718 1.00127.25 A O HETATM 4 O3 MG6 A 1 -55.370 118.284 92.428 1.00127.74 A O HETATM 5 O4 MG6 A 1 -53.253 119.219 90.518 1.00128.43 A O HETATM 6 O5 MG6 A 1 -54.385 115.379 91.937 1.00127.84 A O HETATM 7 O6 MG6 A 1 -52.566 116.391 89.994 1.00128.62 A O " LigandFit automatically runs the elbow and creates a new search pdb file with hydroges and while doing this, elbow totally screws up the original starting geometry of the Oxygen atoms within the cluster after the addition of hydrogens. "HETATM 1 MG MG6 A 1 -53.913 117.323 91.231 1.00128.70 A MG HETATM 2 O1 MG6 A 1 -55.140 117.947 90.141 1.00128.62 A O HETATM 3 O2 MG6 A 1 -53.080 118.061 92.589 1.00127.25 A O HETATM 4 O3 MG6 A 1 -55.453 117.480 92.061 1.00127.74 A O HETATM 5 O4 MG6 A 1 -52.768 118.528 90.669 1.00128.43 A O HETATM 6 O5 MG6 A 1 -53.676 115.727 91.923 1.00127.84 A O HETATM 7 O6 MG6 A 1 -53.363 116.194 90.004 1.00128.62 A O HETATM 8 H11 MG6 A 1 -55.461 117.161 89.473 1.00128.62 A H HETATM 9 H21 MG6 A 1 -52.333 117.378 92.967 1.00127.25 A H HETATM 10 H31 MG6 A 1 -55.430 118.350 92.700 1.00127.74 A H HETATM 11 H41 MG6 A 1 -53.300 119.422 90.378 1.00128.43 A H HETATM 12 H51 MG6 A 1 -54.636 115.255 92.077 1.00127.84 A H HETATM 13 H61 MG6 A 1 -52.319 116.372 89.793 1.00128.62 A H " Is it a bug or am I making something wrong? Does the search pdb HAVE TO be covalently linked? or can I search for a cluster? Thanks. -- Hasan DeMirci