Properties TableAll Structures
AlaCysAspGluPheGlyHisIleLysLeu
MetAsnProGlnArgSerThrValTrpTyr
Atomic naming in PDB consists of 4 character field: atomic symbol (2 char), remoteness indicator (1 char), branch designator (1 char).
Remoteness indcator uses Greek letter distance abbreviation. In order of increasing distance, these are A for alpha, B for beta, G for gamma, D for delta, E for epsilon, Z for zeta, and H for eta.
Branch designator: digit designating the branch direction; left blank if the sidechain is unbranched.
Color scheme: Red=Oxygen; Gray=Carbon; Blue=Nitrogen; Cyan=Hydrogen; Yellow=Sulphur

Histidine


AAH
CodeHis
FullnameHistidine
Side chain typebasic
Mass155.16
pI7.6
pK1(a-COOH)1.8
pK2(a-+NH3)9.33
pKr (R)6.04
hydrophobicX
positiveX
negative-
polarX
chargedX
small-
tiny-
aromaticX
aliphatic-
van der Waals volume118
Remarks "In even slightly acidic conditions protonation of the nitrogen occurs, changing the properties of histidine and the polypeptide as a whole. It is used by many proteins as a regulatory mechanism, changing the conformation and behavior of the polypeptide in acidic regions such as the late endosome or lysosome."