The regular hexagonal surface layer of Halobacterium cutirubrum: a honeycomb network

Abstract

The regular surface pattern of Halobacterium cutirubrum, as studied from replicas, appears to be made up of spherical subunits in hexagonal array. Low-beam intensity studies of cells dried from salt solutions revealed a regular honeycomb network containing hexagonal holes 9.5 to 11.0 nm in diameter with a center-to-center repeat distance of 15.5 to 17.0 nm. These structures appeared to be negatively stained by NaCl or heavy cations adsorbed from the growth medium. This network shares a number of common features with the perforate outer layer of Lampropedia hyalina.