Figure 3 .

Sequence alignment of barnases from B. amyloliquefaciens and B. circulans. The barnase sequences were aligned with Clustal Omega. Gray shading marks the SP of the B. amyloliquefaciens barnase (P00648), which is absent from the barnase of B. circulans (P35078). Depending on the selected SCL prediction approach, P35078 would either be assigned as an extracellular protein since it belongs to a family of extracellular RNases, or as a cytosolic protein since it lacks a SP. Clearly, in absence of an appropriate SP, bacterial export of a protein with the P35078 sequence is unlikely.