Within this thesis several proteins from H. pylori, important for survival of the bacterium, were structurally characterized (HpFlgD, CrdA, HP1026). Crystal structure of the truncated form of the HpFlgD protein revealed that spatial orientation of the two domains differs from that of the homologous FlgD family members. This fact together with the observation that truncated HpFlgD assembles into tetramers, both in the solution and in the crystal form, strongly suggests that significant differences exist in the molecular organization of the flagella in different bacterial species. It was shown that incubation of the putative copper binding CrdA protein with Cu2+ ions favours formation of monomeric species in solution and that CrdA binds Cu2+ with very low affinity which is a property of copper trafficking proteins. Functional assays of the HP1026 protein demonstrated for the first time its ATPase activity. While proteins that belong to the class of AAA+ proteins usually form hexamers, HP1026 was found to form dimers.

U sklopu ove disertacije strukturno su okarakterizirani proteini iz bakterije H. pylori koji su važni za njezino preživljavanje (HpFlgD, CrdA, HP1026). Riješena kristalna struktura skraćenog proteina HpFlgD ukazala je na drugačiju međusobnu orijentaciju dviju domena nego što je nađeno u ostalim homolozima proteina FlgD. Također je pokazano da je skraćeni HpFlgD i u otopini i kristalu prisutan kao tetramer što ukazuje na značajnu razliku u molekularnoj organizaciji biča u različitih bakterijskih vrsta. Uočeno je da dodatak iona Cu2+ u otopinu CrdA, proteina koji pretpostavljeno veže bakrove ione, potiče stvaranje monomernih vrsta u otopini te da CrdA veže ione Cu2+ sa slabim afinitetom što je karakteristika proteina koji prenose bakrove ione. Funkcionalna karakterizacija proteina HP1026 je po prvi put demonstrirala da HP1026 obavlja ATPaznu aktivnost. Iako se proteni koji spadaju u skupinu AAA+ proteina najčešće udružuju kao heksameri, za HP1026 je pokazano da u otopini stvara dimerne vrste.