The DNA of a bacterial cell,such as Escherichia coli is a circular double-stranded molecule  often  referred  to as the bacterial  chromosome.  The circular  DNA  is packaged into a area of the cell called as the nucleoid where it is organized  into 50 or so loops  or domains  which are bound  to a central  protein scaffold  attached  to  the  cell  membrane. Above figure illustrates these industries, though only six loops are shown for clarity. Within this structure the DNA is in fact  not a circular  double-stranded  DNA  molecule  like  as that  shown  in fig.  but is negatively supercoiled,  which is, it is twisted upon itself and is also  completed  with  several  DNA-binding  proteins,  the  most  common  of that are proteins HU, H-NS and HLP-1. These are histone-like proteins.

Figure:  (a) The association of circular bacterial DNA with a protein scaffold; (b) a circular double-stranded DNA molecule; (c) supercoiled DNA.